Method, device and system for thermography

ABSTRACT

A method of determining an internal three-dimensional thermally distinguishable region in the living body is disclosed. The method comprises obtaining a synthesized thermospatial image defined over a three-dimensional spatial representation of the living body and having thermal data arranged gridwise over a surface of the three-dimensional spatial representation in a plurality of picture-elements each represented by a intensity value over the grid. The method further comprises searching over the grid for at least one set of picture-elements represented by generally similar intensity values. For at least a few sets of picture-elements, the method defines a plurality of loci, each locus being associated with at least a pair of picture-elements of the set and defined such that each point of the locus is at equal thermal distances from individual picture-elements of the pair. The plurality of loci is used for determining the internal three-dimensional thermally distinguishable region.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to imaging and, more particularly, tomethod, device and system for obtaining and analyzing thermographicimages.

The use of imaging in diagnostic medicine dates back to the early 1900s.Presently there are numerous different imaging modalities at thedisposal of a physician allowing imaging of hard and soft tissues andcharacterization of both normal and pathological tissues.

Infra red imaging is utilized for characterizing a thermallydistinguishable site in a human body for the purposes of identifyinginflammation. Infrared cameras produce two-dimensional images known asthermographic images. A thermographic image is typically obtained byreceiving from the body of the subject radiation at any one of severalinfrared wavelength ranges and analyzing the radiation to provide atwo-dimensional temperature map of the surface. The thermographic imagecan be in the form of either or both of a visual image and correspondingtemperature data. The output from infrared cameras used for infraredthermography typically provides an image comprising a plurality of pixeldata points, each pixel providing temperature information which isvisually displayed, using a color code or grayscale code. Thetemperature information can be further processed by computer software togenerate for example, mean temperature for the image, or a discrete areaof the image, by averaging temperature data associated with all thepixels or a sub-collection thereof.

Based on the thermographic image, a physician diagnoses the site, anddetermines, for example, whether or not the site includes aninflammation while relying heavily on experience and intuition.

U.S. Pat. No. 7,072,504 discloses an approach which utilizes twoinfrared cameras (left and right) in combination with two visible lightcameras (left and right). The infrared cameras are used to provide athree-dimensional thermographic image and the visible light cameras areused to provide a three-dimensional visible light image. Thethree-dimensional thermographic and three-dimensional visible lightimages are displayed to the user in an overlapping manner.

Also of interest is U.S. Pat. No. 6,442,419 disclosing a scanning systemincluding an infrared detecting mechanism which performs a 360° dataextraction from an object, and a signal decoding mechanism, whichreceives electrical signal from the infrared detecting mechanism andintegrates the signal into data of a three-dimensional profile curvedsurface and a corresponding temperature distribution of the object.

International Patent Publication No. 2006/003658, the contents of whichare hereby incorporated by reference, discloses a system which includesnon-thermographic image data acquisition functionality and thermographicimage data acquisition functionality. The non-thermographic image dataacquisition functionality acquires non-thermographic image data, and thethermographic image data acquisition functionality acquiresthermographic image data.

There is a widely recognized need for, and it would be highlyadvantageous to have a method, device and system for obtaining andanalyzing thermographic images.

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided amethod of calculating a thermal path in a body. The method comprises (a)associating thermal data with a surface of at least a portion of thebody to thereby generate a thermal data map on the surface; (b)identifying in the thermal data map at least one thermallydistinguishable region; and (c) calculating the thermal path in the atleast a portion of the body based on a surface distribution of the atleast one thermally distinguishable region.

According to further features in preferred embodiments of the inventiondescribed below, (a) is effected by collecting thermal radiation fromthe surface. According to still further features in the describedpreferred embodiments the method further comprises correcting thecollected thermal radiation for emissivity of tissue in the at least theportion of the body.

According to still further features in the described preferredembodiments the at least one thermally distinguishable region comprisesat least two thermally distinguishable region.

According to another aspect of the present invention there is provided amethod of calculating a thermal path in a living body, comprises:obtaining a synthesized thermospatial image defined over athree-dimensional spatial representation of the living body and havingthermal data associated with a surface of the three-dimensional spatialrepresentation. The thermal data are preferably arranged gridwise overthe surface in a plurality of picture-elements each represented by aintensity value over the grid. The method further comprises identifyingat least one thermally distinguishable spot in the thermospatial image,and using the thermospatial image and the thermally distinguishable spotfor calculating the thermal path.

According to further features in preferred embodiments of the inventiondescribed below, the method further comprises using at least two thermaltrajectories so as to determine an internal three-dimensional thermallydistinguishable region in the living body.

According to still further features in the described preferredembodiments the method further comprises: obtaining an additionalsynthesized thermospatial image representing a different posture of theliving body; repeating the thermally distinguishable spot identificationand the gradient calculation so as to determine an internalthree-dimensional thermally distinguishable region corresponding to thedifferent posture; and comparing internal three-dimensional thermallydistinguishable regions corresponding to different postures.

According to yet another aspect of the present invention there isprovided an apparatus for calculating a thermal path in a living body,comprises: an input unit for receiving a synthesized thermospatialimage; a spot identification unit, for identifying at least onethermally distinguishable spot in the synthesized thermospatial image;and a calculator for calculating the thermal path in the living bodybased on the thermospatial image and the thermally distinguishable spot.

According to still further features in the described preferredembodiments the apparatus further comprises a region determination unit,designed and configured for determining an internal three-dimensionalthermally distinguishable region in the living body based on at leasttwo thermal trajectories.

According to still further features in the described preferredembodiments the thermal path is calculated by calculating a spatialgradient of the surface at the spot.

According to yet another aspect of the present invention there isprovided a method of determining an internal three-dimensional thermallydistinguishable region in the living body, the method comprises:obtaining a synthesized thermospatial image; searching over the grid forat least one set of picture-elements represented by generally similarintensity values; and for at least one of the at least one set ofpicture-elements, defining a plurality of loci, each locus beingassociated with at least a pair of picture-elements of the set anddefined such that each point of the locus is at equal thermal distancesfrom individual picture-elements of the pair, and using the plurality ofloci for determining the internal three-dimensional thermallydistinguishable region.

According to still another aspect of the present invention there isprovided an apparatus for determining an internal three-dimensionalthermally distinguishable region in the living body, the apparatuscomprises: an input unit for receiving a synthesized thermospatialimage; a searching unit for searching over the grid for at least one setof picture-element represented by generally similar intensity values; alocus definition unit for defining a plurality of loci, each locus beingassociated with at least a pair of picture-elements of the set anddefined such that each point of the locus is at equal thermal distancesfrom individual picture-elements of the pair; and a region determinationunit for determining the internal three-dimensional thermallydistinguishable region based on the plurality of loci.

According to further features in preferred embodiments of the inventiondescribed below, at least one locus of the plurality of loci is a plane.

According to still further features in the described preferredembodiments the internal three-dimensional thermally distinguishableregion is at least partially bounded by the plurality of loci.

According to still further features in the described preferredembodiments the internal three-dimensional thermally distinguishableregion is determined based on intersecting lines of at least a few ofthe plurality of loci.

According to still further features in the described preferredembodiments the method further comprises locating a source region withinthe internal three-dimensional thermally distinguishable region.

According to still further features in the described preferredembodiments the apparatus further comprises a source region locator, forlocating a source region within the internal three-dimensional thermallydistinguishable region.

According to still further features in the described preferredembodiments the source region is selected from the group consisting of acentroid, a weighted centroid and a center-of-mass of the internalthree-dimensional thermally distinguishable region.

According to an additional aspect of the present invention there isprovided a method of determining a number of thermally distinguishableobjects in the living body, the method comprises: obtaining asynthesized thermospatial image in which the thermal data ischaracterized by closed isothermal contours surrounding at least onethermally distinguished spots on the surface; determining an internalthree-dimensional thermally distinguishable region in the living bodybased on the synthesized thermospatial image; analyzing thethree-dimensional spatial representation so as to define a boundarywithin the three-dimensional spatial representation, wherein pointsresiding on one side of the boundary correspond to a single thermallydistinguished spot on the surface while points residing on another sideof the boundary correspond to a plurality of thermally distinguishedspots on the surface; and comparing the internal three-dimensionalthermally distinguishable region with the boundary so as to determinethe number of thermally distinguishable objects in the living body.

According to yet an additional aspect of the present invention there isprovided apparatus for determining a number of thermally distinguishableobjects in the living body, the apparatus comprises: an input unit forreceiving a synthesized thermospatial image; a region determination unitfor determining an internal three-dimensional thermally distinguishableregion in the living body based on the synthesized thermospatial image;an analyzer for analyzing the three-dimensional spatial representationso as to define a boundary within the three-dimensional spatialrepresentation, wherein points residing on one side of the boundarycorrespond to a single thermally distinguished spot on the surface whilepoints residing on another side of the boundary correspond to aplurality of thermally distinguished spots on the surface; and acomparison unit for comparing the internal three-dimensional thermallydistinguishable region with the boundary so as to determine the numberof thermally distinguishable objects in the living body.

According to further features in preferred embodiments of the inventiondescribed below, the method further comprises acquiring at least onethermographic image and mapping the at least one thermographic image onthe three-dimensional spatial representation so as to form thesynthesized thermospatial image.

According to still further features in the described preferredembodiments the mapping comprises weighting the at least onethermographic image according to emissivity data of the living body.

According to still further features in the described preferredembodiments the at least one thermographic image comprises a pluralityof thermographic images.

According to still further features in the described preferredembodiments at least two of the thermographic images are acquired whenthe living body is at a different posture.

According to still further features in the described preferredembodiments, the at least one additional synthesized thermospatial imagecorresponds to a different posture of the living body.

According to still further features in the described preferredembodiments the method further comprises: obtaining a plurality ofthree-dimensional spatial representations of the living body; for atleast two three-dimensional spatial representations, analyzing eachthree-dimensional spatial representation so as to determine expectedtopology of isothermal contours on a surface of the three-dimensionalspatial representation; and selecting a viewpoint for the at least onethermographic image and/or a posture of the living body based on theexpected topologies.

According to still further features in the described preferredembodiments the method further comprises: obtaining at least oneadditional three-dimensional spatial representation of the living body,corresponding to a different viewpoint with respect to, and/or adifferent posture of, the living body; based on the internalthree-dimensional thermally distinguishable region in the living body,constructing expected topology of isothermal contours on a surface ofthe at least one additional three-dimensional spatial representation;obtaining at least one additional synthesized thermospatial imagecorresponding to the different viewpoint and/or the different posture;comparing the at least one synthesized thermospatial image to theexpected topology of the isothermal contours; and issuing a reportrelating to the comparison.

According to still further features in the described preferredembodiments method further comprises constructing the three-dimensionalspatial representation.

According to still further features in the described preferredembodiments the obtaining the three-dimensional spatial representationcomprises illuminating the body with a pattern in the infrared range,using at least one thermographic imaging device for acquiring at leastone thermographic image of the body and the pattern, calculating rangedata corresponding to the pattern, and using the at least onethermographic image and the range data for constructing thethree-dimensional spatial representation of the body.

According to still an additional aspect of the present invention thereis provided a system for thermospatial imaging of an anterior of aliving body, the system comprises an intracorporeal probe system havingtherein at least one thermographic imaging device for acquiring at leastone thermographic image of the anterior of the living body, and a dataprocessor for analyzing image data received from the intracorporealprobe system so as to provide and display a synthesized thermospatialimage of the anterior of the living body.

According to still further features in the described preferredembodiments the system further comprises at least one visible lightimaging device for acquiring at least one visible light image of theanterior of the living body.

According to still further features in the described preferredembodiments the system further comprises an illuminating device forilluminating the anterior of the body with a pattern.

According to still further features in the described preferredembodiments the intracorporeal probe system is adapted to be insertedthrough the anus.

According to still further features in the described preferredembodiments the intracorporeal probe system is adapted to be insertedthrough the vagina.

According to still further features in the described preferredembodiments the intracorporeal probe system is adapted to be insertedthrough the urethra.

According to still further features in the described preferredembodiments the intracorporeal probe system is adapted to be insertedthrough the esophagus.

According to still further features in the described preferredembodiments the intracorporeal probe system is mounted on a transportmechanism.

According to still further features in the described preferredembodiments the transport mechanism is selected from the groupconsisting of an endoscopic probe and a catheter.

According to a further aspect of the present invention there is provideda method which comprises acquiring a series of thermographic images ofthe living body from a predetermined viewpoint; comparing thethermographic images to extract thermal changes in the thermographicimages; and when the thermal changes are below a predeterminedthreshold, issuing a report indicating that the living body is at agenerally stable thermal condition.

According to still further features in the described preferredembodiments the acquisition and the comparison is performedsubstantially contemporaneously.

According to still further features in the described preferredembodiments at least a few thermographic images are compared to a singlepreviously acquired thermographic image.

According to still further features in the described preferredembodiments at least a few thermographic images are compared to aplurality of previously acquired thermographic images.

According to still further features in the described preferredembodiments the method further comprises displaying the thermal changeson a display device.

According to yet a further aspect of the present invention there isprovided a method of monitoring a position of a medical device in aliving body, comprises setting a temperature of the medical device to atemperature which is sufficiently different from an average temperatureof the living body, forming at least one synthesized thermospatial imageof the living body, and using the at least one synthesized thermospatialimage for monitoring the position of the insertable device in the livingbody.

According to still a further aspect of the present invention there isprovided a medical device insertable into a living body, comprises ahollow structure having a proximal end, a distal end and an opticalfiber extending from the proximal end to the a distal end, the opticalfiber being designed and constructed to transmit thermal radiation fromthe from the distal end to the proximal end.

According to still further features in the described preferredembodiments the hollow structure and the optical fiber are made ofdifferent materials.

According to still further features in the described preferredembodiments the optical fiber is defined by a passageway in the hollowstructure.

According to still a further aspect of the present invention there isprovided an illuminating device for a range imaging system, comprises, alight source for generating a light beam, a dynamic beam deflector andan image forming element having a plurality of distinguished regionseach being designed for forming a different image, wherein the dynamicbeam deflector is designed and configured to scan the image formingelement to form different images at different times.

According to still further features in the described preferredembodiments the light source comprises a laser device, and the lightbeam is a laser beam.

According to still further features in the described preferredembodiments the dynamic beam deflector comprises a movable mirror.

According to still further features in the described preferredembodiments the dynamic beam deflector comprises an electroopticalmaterial.

According to still a further aspect of the present invention there isprovided a method of constructing a three-dimensional spatialrepresentation of a body, the method comprises: illuminating the bodywith a pattern in the infrared range; using at least one thermographicimaging device for acquiring at least one thermographic image of thebody and the pattern; calculating range data corresponding to thepattern; and using the at least one thermographic image and the rangedata for constructing the three-dimensional spatial representation ofthe body.

According to still further features in the described preferredembodiments the acquiring comprises acquiring at least two thermographicimages of the body and the pattern from at least two differentviewpoints.

According to still a further aspect of the present invention there isprovided a system for constructing a three-dimensional spatialrepresentation of a body, comprises: an illuminating device, designedand constructed for illuminating the body with a pattern in the infraredrange; at least one thermographic imaging device designed andconstructed for acquiring at least one thermographic image of the bodyand the pattern; and a data processor designed and configured forcalculating range data corresponding to the pattern, and using the atleast one thermographic image and the range data for constructing thethree-dimensional spatial representation of the body.

According to still further features in the described preferredembodiments the at least one thermographic imaging device is designedand constructed for acquiring at least two thermographic images of thebody and the pattern from at least two different viewpoints.

According to still further features in the described preferredembodiments the pattern is selected to allow construction of athree-dimensional spatial representation by temporal coding.

According to still further features in the described preferredembodiments the pattern is selected to allow construction of athree-dimensional spatial representation by spatial coding.

According to still further features in the described preferredembodiments the range data are calculated by time-of-flight technique.

According to still further features in the described preferredembodiments the range data are calculated by triangulation.

According to still further features in the described preferredembodiments a pulse length characterizing the illumination is shorterthan 20 milliseconds.

According to still further features in the described preferredembodiments the acquisition of the at least one thermographic image ischaracterized by an exposure time which is less than 20 milliseconds.

According to still further features in the described preferredembodiments the acquisition of the at least one thermographic imagecomprises multiple readouts during a single exposure time.

According to still further features in the described preferredembodiments at least two readouts of the multiple readouts are executedaccumulatively.

According to still further features in the described preferredembodiments the illumination is effected by laser light.

According to still further features in the described preferredembodiments the method further comprises, for at least a fewthermographic images, filtering out image data originating from heatgenerated by the body.

According to still further features in the described preferredembodiments the method further comprises acquiring at least onethermographic image of the body without the pattern, wherein thefiltering out the image data comprises subtracting thermographic imagesacquired without the pattern from thermographic images acquired with thepattern.

According to still further features in the described preferredembodiments the image data processor is designed and configured forfiltering out image data originating from heat generated by the body.

According to still further features in the described preferredembodiments the image data processor is designed and configuredsubtracting thermographic images acquired without the pattern fromthermographic images acquired with the pattern thereby to filter out theimage data.

According to still a further aspect of the present invention there isprovided a method of constructing a three-dimensional spatialrepresentation of a body, the method comprises: illuminating the bodywith a series of spots, wherein at least one spot of the series isdistinguishable from all other spots in the series; using at least oneimaging device for acquiring at least two images of the body and theseries of spots from at least two different viewpoints; locating theseries of spots in each image; in each image, identifying the at leastone distinguishable spot and using the at least one distinguishable spotfor identifying all other spots in the series; and calculating rangedata for the series of spots and using the range data for constructingthe three-dimensional spatial representation of the body.

According to still a further aspect of the present invention there isprovided a method of calibrating a range imaging system, comprises:accessing a database of figures which comprises a plurality of entries,each having a figure entry and an angle entry corresponding to aviewpoint of the figure entry; illuminating the body with a figure;using at least one imaging device for acquiring at least two images ofthe body and the figure from at least two different viewpoints; for atleast two images, identifying the figure, searching over the databasefor a figure entry being generally similar to the figure and extractinga respective angle entry from the database, thereby providing at leasttwo angles; based on the at least two angles, calculating range data forthe figure and using the range data for calibrating the range imagingsystem.

According to still a further aspect of the present invention there isprovided a method of calibrating a thermospatial imaging system, thesystem having at least one at least one thermographic imaging device andat least one visible light imaging device, the method comprises:illuminating a body with a pattern in a plurality of wavelengths,wherein at least one wavelength of the plurality of wavelengths isdetectable by the one at least one thermographic imaging device and atleast one wavelength of the plurality of wavelengths is detectable bythe one at least one visible light imaging device; using the at leastone at least one thermographic imaging device for acquiring at least onethermographic image of the pattern, and at least one visible lightimaging device for acquiring at least one visible light image of thepattern; and calibrating the three-dimensional thermographic imagingdevice using the thermographic and the visible light images.

According to still further features in the described preferredembodiments the at least one thermographic image and at least onevisible light image are acquired substantially simultaneously.

According to still a further aspect of the present invention there isprovided a method of constructing a three-dimensional spatialrepresentation of a body, the method comprises: illuminating the bodywith coded patterns using a pattern projector operable to generate atleast two different colors of light, in a manner such that codedpatterns of different colors are mutually shifted; acquiring at leastone image of the coded pattern to provide image data; and calculatingthree-dimensional positions of the coded patterns based on the imagedata, thereby constructing a three-dimensional spatial representation ofthe body.

According to still a further aspect of the present invention there isprovided a system for constructing a three-dimensional spatialrepresentation of a body, the system comprises: a pattern projectoroperable to illuminate the body with coded patterns of at least twodifferent colors of light in a manner such that coded patterns ofdifferent colors are mutually shifted; an imaging device for acquiringat least one image of the coded pattern, thereby to provide image data;and an image data processor designed and configured for calculatingthree-dimensional positions of the coded patterns, based on the imagedata.

According to still further features in the described preferredembodiments the at least two coded patterns are mutually shifted by onepixel size.

According to still further features in the described preferredembodiments the pattern projector is operable to project coded patternsof different colors sequentially.

According to still further features in the described preferredembodiments coded patterns of different colors are mutually shifted byan amount which is lower than the characteristic distance betweencenters of adjacent projected pixels.

According to still further features in the described preferredembodiments the acquisition of the at least one image is characterizedby an exposure time which is less than 20 milliseconds.

According to still further features in the described preferredembodiments the acquisition of the at least one image comprises multiplereadouts during a single exposure time.

According to still further features in the described preferredembodiments the at least two different colors comprise a first color asecond color and a third color and the acquisition of the at least oneimage comprises three readouts during a single exposure time.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of the present invention, suitable methods andmaterials are described below. In case of conflict, the patentspecification, including definitions, will control. In addition, thematerials, methods, and examples are illustrative only and not intendedto be limiting.

Implementation of the method and system of the present inventioninvolves performing or completing selected tasks or steps manually,automatically, or a combination thereof. Moreover, according to actualinstrumentation and equipment of preferred embodiments of the method andsystem of the present invention, several selected steps could beimplemented by hardware or by software on any operating system of anyfirmware or a combination thereof. For example, as hardware, selectedsteps of the invention could be implemented as a chip or a circuit. Assoftware, selected steps of the invention could be implemented as aplurality of software instructions being executed by a computer usingany suitable operating system. In any case, selected steps of the methodand system of the invention could be described as being performed by adata processor, such as a computing platform for executing a pluralityof instructions.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, withreference to the accompanying drawings. With specific reference now tothe drawings in detail, it is stressed that the particulars shown are byway of example and for purposes of illustrative discussion of thepreferred embodiments of the present invention only, and are presentedin the cause of providing what is believed to be the most useful andreadily understood description of the principles and conceptual aspectsof the invention. In this regard, no attempt is made to show structuraldetails of the invention in more detail than is necessary for afundamental understanding of the invention, the description taken withthe drawings making apparent to those skilled in the art how the severalforms of the invention may be embodied in practice.

In the drawings:

FIGS. 1 a-c are schematic illustrations of a 3D spatial representation(FIG. 1 a), a thermographic image (FIG. 1 b), and a synthesizedthermospatial image formed by mapping the thermographic image on asurface of the 3D spatial representation (FIG. 1 c), according tovarious exemplary embodiments of the present invention;

FIG. 2 is a is a flowchart diagram describing a method suitable forcalculating a thermal path in a living body, according to variousexemplary embodiments of the present invention;

FIG. 3 a is a schematic illustration of a procedure in which a gradientis used to define a thermal path in the body;

FIG. 3 b is a schematic illustration of a procedure for determining thelocation of an internal three-dimensional thermally distinguishableregion using two or more thermal trajectories;

FIG. 4 is a schematic illustration of an apparatus for calculating athermal path in a living body, according to various exemplaryembodiments of the present invention;

FIG. 5 is a flowchart diagram describing a method suitable fordetermining the position and optionally the size of an internalthree-dimensional thermally distinguishable region in the living body,according to various exemplary embodiments of the present invention;

FIG. 6 a is a schematic illustration of a procedure for defining alocus, according to various exemplary embodiments of the presentinvention;

FIGS. 6 b-d are schematic illustrations three-dimensional regions whichare bounded by several planar loci, according to various exemplaryembodiments of the present invention;

FIG. 6 e illustrates a line along which two loci intersect, according tovarious exemplary embodiments of the present invention;

FIG. 6 f illustrates a plurality of points which are the intersectionpoints of two or more lines, according to various exemplary embodimentsof the present invention;

FIG. 7 is a schematic illustration of an apparatus for determining aninternal three-dimensional thermally distinguishable region in theliving body, according to various exemplary embodiments of the presentinvention;

FIG. 8 is a flowchart diagram of a method 80 suitable for determining anumber of thermally distinguishable objects in the living body,according to various exemplary embodiments of the present invention;

FIGS. 9 a-b are schematic illustrations of thermal data characterized byclosed isothermal contours (FIG. 9 a) and open isothermal contours (FIG.9 b), according to various exemplary embodiments of the presentinvention;

FIGS. 10 a-e are schematic illustrations describing a procedure fordefining a boundary within a 3D spatial representation, such that thatpoints residing on one side of the boundary correspond to a singlethermally distinguished spot on the surface of the 3D spatialrepresentation, while points residing on another side of the boundarycorrespond to a plurality of thermally distinguished spots on thesurface of the 3D spatial representation, according to various exemplaryembodiments of the present invention;

FIG. 11 is a schematic illustration of apparatus for determining anumber of thermally distinguishable objects in the living body,according to various exemplary embodiments of the present invention;

FIGS. 12 a-f and 13 a-e are schematic illustration of a thermospatialimaging system, according to various exemplary embodiments of thepresent invention;

FIG. 14 is a schematic illustration of illumination in the form of aseries of spots, where at least one spot of the series isdistinguishable from all other spots, according to various exemplaryembodiments of the present invention;

FIG. 15 is a flowchart diagram of a method suitable for constructing a3D spatial representation of a body, according to various exemplaryembodiments of the present invention;

FIGS. 16 a-c are schematic illustrations of exposure times and readouttimes, according to various exemplary embodiments of the presentinvention;

FIG. 17 is a schematic illustration of a system for constructing athree-dimensional spatial representation of a body, according to variousexemplary embodiments of the present invention;

FIGS. 18 a-c are schematic illustrations of a thermospatial imagingsystem, according to various exemplary embodiments of the presentinvention;

FIGS. 19 a-c are schematic illustrations showing uses of anintracorporeal probe system according to various exemplary embodimentsof the present invention;

FIG. 20 is a flowchart diagram of a method suitable for assessing theaccuracy of the determination of the internal thermally distinguishedregions in the body, according to various exemplary embodiments of thepresent invention;

FIG. 21 is a flowchart diagram of a method suitable for ensuring that aliving body is at a generally stable thermal condition, according tovarious exemplary embodiments of the present invention;

FIG. 22 is a schematic illustration of medical device insertable into aliving body, according to various exemplary embodiments of the presentinvention;

FIGS. 23 a-b are schematic illustrations of an illuminating devicesuitable for thermospatial imaging, according to various exemplaryembodiments of the present invention;

FIG. 24 is a flowchart diagram of another method suitable forconstructing a 3D spatial representation of a body, in accordance withpreferred embodiments of the present invention;

FIG. 25 is a schematic illustration of another system for constructing a3D spatial representation of a body, in accordance with preferredembodiments of the present invention; and

FIGS. 26 a-d is a schematic illustration of mutually shifted patterns,according to various exemplary embodiments of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present embodiments comprise a method, apparatus and system whichcan be used in imaging. Specifically, but not exclusively the presentembodiments can be used to determine the position of internal thermallydistinguishable region in a living body.

The principles and operation of a method, apparatus and system accordingto the present embodiments may be better understood with reference tothe drawings and accompanying descriptions.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not limited in its applicationto the details of construction and the arrangement of the components setforth in the following description or illustrated in the drawings. Theinvention is capable of other embodiments or of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein is for the purpose ofdescription and should not be regarded as limiting.

The present inventors have devised an approach which enables detectionand localization of a tissue region of interest (e.g., a pathology suchas a tumor) from the thermal path or trajectory leading from such atissue region to a surface overlying the tissue region.

Several approaches for such trajectory or path calculations arecontemplated herein. One such approach exploits a thermal data map whichincludes thermal data associated with a surface of at least a portion ofthe body. One or more thermally distinguishable region are identified inthe thermal data map. In various exemplary embodiments of the inventionthe thermally distinguishable region(s) are then characterized in as faras surface distribution (e.g., pattern of thermal region), position onthe surface, thermal intensity, size, position with respect to otherthermally distinguishable regions. Such characterizing features arepreferably utilized to calculate the thermal path in the body.

Thus, preferred embodiments of the invention relate generally to theanalysis of surface information such as to extract properties of theunderlying tissue. In various exemplary embodiments of the invention thesurface information comprise spatial information as well as thermalinformation.

The spatial information comprises geometric properties of a non-planarsurface which at least partially encloses a three-dimensional volume.Generally, the non-planar surface is a two-dimensional object embeddedin a three-dimensional space. Formally, a non-planar surface is a metricspace induced by a smooth connected and compact Riemannian 2-manifold.Ideally, the geometric properties of the non-planar surface would beprovided explicitly for example, the slope and curvature (or even otherspatial derivatives or combinations thereof) for every point of thenon-planar surface. Yet, such information is rarely attainable and thespatial information is provided for a sampled version of the non-planarsurface, which is a set of points on the Riemannian 2-manifold and whichis sufficient for describing the topology of the 2-manifold. Typically,the spatial information of the non-planar surface is a reduced versionof a 3D spatial representation, which may be either a point-cloud or a3D reconstruction (e.g., a polygonal mesh or a curvilinear mesh) basedon the point cloud. The 3D spatial representation is expressed via a 3Dcoordinate system, such as, but not limited to, Cartesian, Spherical,Ellipsoidal, 3D Parabolic or Paraboloidal coordinate 3D system. The term“surface” is used herein as an abbreviation of the term “non-planarsurface”.

The thermal information comprises data pertaining to heat evacuated fromor absorbed by the surface. Since different parts of the surfacegenerally evacuate or absorb different amount of heat, the thermalinformation comprises a set of tuples, each comprising the coordinatesof a region or a point on the surface and a thermal value (e.g.,temperature, thermal energy) associated with the point or region. Thethermal information can be transformed to visible signals, in which casethe thermal information is in the form of a thermographic image. Theterms “thermographic image” and thermal information are usedinterchangeably throughout the specification without limiting the scopeof the present invention in any way. Specifically, unless otherwisedefined, the use of the term “thermographic image” is not to beconsidered as limited to the transformation of the thermal informationinto visible signals. For example, a thermographic image can be storedin the memory of a computer readable medium as a set of tuples asdescribed above.

The surface information (thermal and spatial) of a body is typically inthe form of a synthesized 3D image which includes both thermal data andspatial data on the same 3D image. Such image is referred to as athermospatial image.

It is appreciated that a three-dimensional image of a body is typicallya two-dimensional image which, in addition to indicating the lateralextent of body members, further indicates the relative or absolutedistance of the body members, or portions thereof, from some referencepoint, such as the location of the imaging device. Thus, athree-dimensional image typically includes information residing on anon-planar surface of a three-dimensional body and not necessarily inthe bulk. Yet, it is commonly acceptable to refer to such image as“three-dimensional” because the non-planar surface is convenientlydefined over a three-dimensional system of coordinate. Thus, throughoutthis specification and in the claims section that follows, the terms“three-dimensional image” and “three-dimensional representation”primarily relate to surface entities.

The thermospatial image is defined over a 3D spatial representation ofthe body and has thermal data associated with a surface of the 3Dspatial representation, and arranged gridwise over the surface in aplurality of picture-elements (e.g., pixels, arrangements of pixels)each represented by an intensity value or a grey-level over the grid. Itis appreciated that the number of different intensity value can bedifferent from the number of grey-levels. For example, an 8-bit displaycan generate 256 different grey-levels. However, in principle, thenumber of different intensity values corresponding to thermalinformation can be much larger. As a representative example, supposethat the thermal information spans over a range of 37° C. and isdigitized with a resolution of 0.1° C. In this case, there are 370different intensity values and the use of grey-levels is less accurateby a factor of approximately 1.4. Thus, in various exemplary embodimentsof the invention the processing of thermal data is performed usingintensity values rather than grey-levels. Yet the use of grey-level isnot excluded from the scope of the present invention.

The term “pixel” is sometimes abbreviated herein to indicate apicture-element. However, this is not intended to limit the meaning ofthe term “picture-element” which refers to a unit of the composition ofan image.

Typically, one or more thermographic images are mapped onto the surfaceof the 3D spatial representation to form the thermospatial image. Thethermographic image to be mapped onto the surface of the 3D spatialrepresentation preferably comprises thermal data which are expressedover the same coordinate system as the 3D spatial representation. Anytype of thermal data can be used. In one embodiment the thermal datacomprises absolute temperature values, in another embodiment the thermaldata comprises relative temperature values each corresponding, e.g., toa temperature difference between a respective point of the surface andsome reference point, in an additional embodiment, the thermal datacomprises local temperature differences. Also contemplated, arecombinations of the above types of temperature data, for example, thethermal data can comprise both absolute and relative temperature values,and the like. Typically, the information in the thermographic image alsoincludes the thermal conditions (e.g., temperature) at the referencemarkers.

The mapping of the thermographic image onto the surface of the 3Dspatial representation is by accurately positioning the referencemarkers, for example (e.g., by comparing their coordinates in thethermographic image with their coordinates in the 3D spatialrepresentation), to thereby match also other points hence to form thesynthesized thermospatial image.

Optionally and preferably, the mapping of thermographic images isaccompanied by a correction procedure in which thermal emissivityconsiderations are employed.

The thermal emissivity of a body member is a dimensionless quantitydefined as the ratio between the amount of thermal radiation emittedfrom the surface of the body member and the amount of thermal radiationemitted from a black body having the same temperature as the bodymember. Thus, the thermal emissivity of an idealized black body is 1 andthe thermal emissivity of all other bodies is between 0 and 1. It iscommonly assumed that the thermal emissivity of a body is generallyequal to its thermal absorption factor.

The correction procedure can be performed using estimated thermalcharacteristics of the body of interest. Specifically, the thermographicimage is mapped onto a non-planar surface describing the body takinginto account differences in the emissivity of regions on the surface ofthe body. A region with a different emissivity value compared to itssurrounding, can be, for example, a scared region, a pigmented region, anipple region on the breast, a nevus. Additionally, the emissivityvalues of subjects with different skin colors may differ.

In a preferred embodiment, the thermographic image is weighted accordingto the different emissivity values of the surface. For example, wheninformation acquired by a thermal imaging device include temperature orenergy values, at least a portion of the temperature or energy valuescan be divided by the emissivity values of the respective regions on thesurface of the body. One of ordinary skill in the art will appreciatethat such procedure results in effective temperature or energy valueswhich are higher than the values acquired by the thermal imaging device.Since different regions may be characterized by different emissivityvalues, the weighted thermographic image provides better estimateregarding the heat emitted from the surface of the body.

A representative example of a synthesized thermospatial image for thecase that the body comprise the breasts of a woman is illustrated inFIGS. 1 a-c, showing a 3D spatial representation illustrated as anon-planar surface (FIG. 1 a), a thermographic image illustrated asplanar isothermal contours (FIG. 1 b), and a synthesized thermospatialimage formed by mapping the thermographic image on a surface of the 3Dspatial representation (FIG. 1 c). As illustrated, the thermal data ofthe thermospatial image is represented as grey-level values over a gridgenerally shown at 102. It is to be understood that the representationaccording to grey-level values is for illustrative purposes and is notto be considered as limiting. As explained above, the processing ofthermal data can also be performed using intensity values. Also shown inFIGS. 1 a-c, is a reference marker 101 used for the mapping.

The 3D spatial representation, thermographic image and synthesizedthermospatial image can be obtained in any technique known in the art,such as the technique disclosed in International Patent Publication No.WO 2006/003658, U.S. Published Application No:20010046316, and U.S. Pat.Nos. 6,442,419, 6,765,607, 6,965,690, 6,701,081, 6,801,257, 6,201,541,6,167,151, 6,167,151 and 6,094,198. The present embodiments also provideother techniques for obtaining the surface information or a part thereofas further detailed hereinunder.

Preferred embodiments of the invention can be embodied on a tangiblemedium such as a computer for performing the method steps. Preferredembodiments of the invention can be embodied on a computer readablemedium, comprising computer readable instructions for carrying out themethod steps. Preferred embodiments of the invention can also beembodied in electronic device having digital computer capabilitiesarranged to run the computer program on the tangible medium or executethe instruction on a computer readable medium. Computer programsimplementing method steps of the present embodiments can commonly bedistributed to users on a tangible distribution medium. From thedistribution medium, the computer programs can be copied to a hard diskor a similar intermediate storage medium. The computer programs can berun by loading the computer instructions either from their distributionmedium or their intermediate storage medium into the execution memory ofthe computer, configuring the computer to act in accordance with themethod of this invention. All these operations are well-known to thoseskilled in the art of computer systems.

The present embodiments are useful in many medical and otherapplications.

For example, the present embodiments can be used for determining thepresence, position and optionally size of internal tumors orinflammations, hence to aid, e.g., the diagnosis of cancer.

The present embodiments are also useful for constructing blood vesselsmap or for determining the location a specific blood vessel within thebody because the temperature of the blood vessel is generally differentfrom the temperature of tissue. In this respect, the present embodimentsare also useful in the area of face recognition, because the knowledgeof blood vessel positions in the face may aid in the identification ofcertain individuals. Recognition of other organs is also contemplated.Organ recognition using the present embodiments is particularlyadvantageous due to the ability of the present embodiments to localizethermally distinguishable regions in the living body. Such localizationcan be used for constructing blood vessel map which provides informationregarding both orientation and depth of blood vessels in the body. Themap can then be used for identifying individuals, e.g., by searching forsimilar map on a accessible and searchable database of blood vesselmaps.

The present embodiments are also useful for bone imaging, because thetemperature of bones is generally different from the temperature of softtissue. This is particularly useful in medical conduction such asscoliosis and other spinal deformities in which it is required toregularly monitor the shape of the bones. In such and other conditionsthe present embodiments provide a safe substitute to the hazardous X-rayimaging.

Bone imaging can also be used for assessing the likelihood ofosteoporosis symptoms. Specifically, since there is generally more heatin the anterior of a healthy bone than on the surface thereof,likelihood of bone mineral density reduction can be identified bymonitoring temperature evolution of the bone surface. For example, aseries of thermospatial image can be obtained and analyzed according topreferred embodiments of the present invention at certain intervals(e.g., once a month or the like) so as to determine whether or not thetemperature on the surface of the bone consistently increases with time.The analysis can be used for assessing the likelihood of bone mineraldensity reduction, whereby more significant rate of temperature increasecorrespond to higher likelihood.

Referring now to the drawings, FIG. 2 is a flowchart diagram describinga method 10 suitable for calculating a thermal path in a living body. Itis to be understood that, unless otherwise defined, the method stepsdescribed hereinbelow can be executed either contemporaneously orsequentially in many combinations or orders of execution. Specifically,the ordering of the flowchart diagrams is not to be considered aslimiting. For example, two or more method steps, appearing in thefollowing description or in the flowchart diagrams in a particularorder, can be executed in a different order (e.g., a reverse order) orsubstantially contemporaneously. Additionally, several method stepsdescribed below are optional and may not be executed.

Method 10 can be used for determining a path on which a thermallydistinguishable object resides within the body. A thermallydistinguishable object is an object having a temperature which is higheror lower than the temperature of their immediate surroundings, and canbe for example, an inflammation, a benign tumor, a malignant tumor andthe like.

The method begins at step 12 and continues to step 14 in which asynthesized thermospatial image of the living body is obtained. Thesynthesized thermospatial image, as stated, is defined over a 3D spatialrepresentation of the body and has thermal data associated with asurface of the 3D spatial representation. The thermospatial image can begenerated by method 10 or it can be generated by another method orsystem from which the image can be read by method 10.

The method continues to step 16 in which one or more thermallydistinguishable spots are identified in the thermospatial image. A“thermally distinguishable spot” refers to an area over the surface ofthe 3D spatial representation for which the thermal data associatedtherewith differ from the thermal data associated with the immediatesurrounding of the region. For example, a thermally distinguishable spotcan be an area at which the temperature reaches a local maximum or alocal minimum. In the exemplified illustration of a thermallydistinguishable spot is generally shown at 201 (see FIG. 1 c). The sizeof the thermally distinguishable spot is typically much smaller than thesize of the thermospatial image.

The method continues to step 18 in which a spatial gradient to thesurface is calculated for at least a few thermally distinguishablespots. Calculations f spatial gradients are known in the art, and methodform calculating such gradients are found in many textbooks. Forexample, when the 3D spatial representation is in the form of polygonalmesh, the spatial gradient can be a vector passing through the spot anddirected perpendicularly to the respective polygon. For a point cloud orother types of 3D representations, the gradient can be found by means offirst spatial derivatives, or by means of tangential planes. Once thegradient is calculated, it is preferably used, together with thelocation of the spot, to define a straight line which can be the thermalpath in the body. For example, when the living body includes a hotobject, such as a method 10 is used for determining a path on which athermally distinguishable object such as an inflammation or a tumor, thestraight line can be define as a path along which heat propagates in thebody.

The procedure is illustrated in FIG. 3 a, showing thermallydistinguished spot 201 on a surface 205 of the 3D spatial representation206. A gradient 202 points inward the 3D spatial representation and apath 203 is defined as a straight line parallel to gradient 202 andpassing through spot 201. Also shown is the location of internalthree-dimensional thermally distinguishable region in the living body asrepresented by an internal region 204 in representation 206. As shown,path 203 also passes through region 204. Once found, the path ispreferably displayed or recorded on a tangible medium, such as a displaydevice, a hard copy a memory medium.

In various exemplary embodiments of the invention the method continuesto step 22 in which two or more thermal trajectories are used todetermine the location of an internal three-dimensional thermallydistinguishable region in the living body. This procedure is illustratedin FIG. 3 b, showing also a second 203′, corresponding to a second spot201′ and a second gradient 202′. The location of region 204 can beobtained by calculating the intersection between the two trajectories,or, when the trajectories do not intersect, as the region between theclosest points of the trajectories. Once found, the internalthree-dimensional thermally distinguishable region is preferablydisplayed or recorded on a tangible medium. Preferably, the methodcontinues to step 24 in which a source region 208 is located withinregion 204. The source region corresponds to the location of a thermallydistinguished object within the body (e.g., an inflammation, a tumor)and can be located by any mathematical procedure known in the art,including, without limitation, a centroid, a weighted centroid and acenter-of-mass of region 204.

According to a preferred embodiment of the present invention the methodloops back to step 14 in which an additional thermospatial image isobtained, which additional thermospatial image corresponds to adifferent posture of the living body. For example, when the living bodyis the breast of a woman, the first thermospatial image can describe thebreast when the woman is standing and the additional thermospatial imagecan describe the breast when the woman bends forwards or lying in proneposition. Preferably, but not obligatorily, the additional thermospatialimage is obtained such that the two or more thermospatial imagesalignable with respect to a predetermined fixed reference point on thebody. For example, the reference point can be a mark on the arm-pit. Theidentification of the thermally distinguishable spot(s) and thecalculation of the gradient(s) is preferably repeated for the additionalthermospatial image, so as to determine the location of the internalthree-dimensional thermally distinguishable region when the body is inthe second posture. The locations determined in the different posturescan then be compared to assess the accuracy of the procedure. A reportregarding the assessed accuracy can then be issued, e.g., on a displaydevice, a hard copy or the like.

Alternatively, the locations can be averaged and the average location ofthe internal three-dimensional thermally distinguishable region can bedisplayed or recorded on a tangible medium.

Method 10 ends at step 26.

FIG. 4 is a schematic illustration of an apparatus 40 for calculating athermal path in a living body, according to various exemplaryembodiments of the present invention. Apparatus 40 can be used forexecuting one or more of the method steps of method 10.

Apparatus 40 comprises an input unit 42 which receiving the synthesizedthermospatial image, a spot identification unit 44 which identifies thethermally distinguishable spot(s), and a gradient calculator 46 forcalculating the spatial gradient as further detailed hereinabove.Apparatus 40 optionally and preferably comprises a region determinationunit 48 which is designed and configured for determining an internalthree-dimensional thermally distinguishable region as further detailedhereinabove. Apparatus 40 can also comprise a source region locator 48which locates the source region as further detailed hereinabove.

Reference is now made to FIG. 5 which is a flowchart diagram of a method50 suitable for determining the position and optionally the size of aninternal three-dimensional thermally distinguishable region in theliving body, according to various exemplary embodiments of the presentinvention.

The method begins at step 52 and continues to step 54 in which asynthesized thermospatial image is obtained. The thermospatial image canbe generated by method 50 or it can be generated by another method orsystem from which the image can be read by method 50.

The method continues to step 56 in which the surface, or morespecifically, the grid 102 is searched for one or more sets ofpicture-elements represented by generally similar intensity values.Formally, the grid is searched for a set of picture-elements having inintensity value of from I−ΔI to I+ΔI, where, I is a predeterminedintensity characterizing the set and ΔI is a width parameter. The valueof ΔI is preferably selected as small as possible but yet sufficientlylarge to allow collection of a sufficient number of picture-elements(say, more than 10 picture-elements) in the set. For example, when theintensity value in each picture-element is a number from 0 to 255, ΔIcan be about 10 units of intensity.

As used herein the term “about” refers to ±20%.

When more than one sets of picture-element are defined, each set ischaracterized by a different intensity I, but two sets may or may nothave equal width parameters.

The search for sets of picture-elements represented by generally similarintensity values can also be accompanied by an averaging procedure. Forexample, the search can begin by locating a thermally distinguished spotor region on the surface. The intensity values of pixels orpicture-elements in the located spot or region are then averaged orweighted averaged to provide an average intensity value. The method canthen search for other regions or spots having the same or similaraverage intensity value. If no matches are found, the method optionallyand preferably recalculates the average intensity value using thepicture-element in the thermally distinguished region andpicture-element surrounding the region, hence expanding the region. Themethod can then search for other regions using the new average. Thisprocess can be iterated a few times as desired. Thus, in thisembodiment, the set is characterized by the average intensity value.

The method continues to step 58 in which a plurality of loci are definedfor one or more of the sets of picture-elements. Each locus of theplurality of loci is associated with at least a pair of picture-elementsof the set and defined such that each point of the locus is at equalthermal distances from individual picture-elements of the pair. Theprocedure is illustrated in FIG. 6 a, which is a fragmentary viewshowing a cross section of surface 205 and pair of picture-elements 601and 602 having generally similar intensity values (hence belonging tothe same set). A locus 603 of points is associated with points 601 and602. A distance d₁ defined between a point 604 of locus 603 and point601 equals a distance d₂ defined between the same point 604 of locus 603and point 602. Generally, the distances d₁ and d₂ are determined fromthe standpoint of a thermal distance based on thermal conductivityrather than from the standpoint of a geometrical distance. Yet, in someembodiments the body can be modeled as a thermally isotropic medium inwhich case the definition of a thermal distance coincides with thedefinition of geometric distance.

Locus 603 can have any shape either planar or non planar. It isappreciated that when the distances d₁ and d₂ are geometrical distances,locus 603 is a plane. Each pair of points may, in principle, beassociated with a different locus. Thus, when the set includes more thanone pair of points, a plurality of loci is defined. Once the loci aredefined the method continues to step 60 in which the loci are used todefine the internal three-dimensional thermally distinguishable region.This can be done in more than one way. In one embodiment, the internalregion is fully or partially bounded by the loci. In other words, theloci are used for defining the external surface of the region. Thisembodiment is illustrated in FIGS. 6 b-d, showing examples ofthree-dimensional regions 204 bounded by several planar loci, designatedby reference signs 603, 603′, 603″.

In another embodiment, the internal region is determined based onintersecting lines of two or more of the loci. This embodiment isillustrated in FIG. 6 e-f, showing a line 605 along which two loci 603and 603′ intersect (FIG. 6 e), and a plurality of points 606 which arethe intersection points of two or more lines 605 (FIG. 6 f). Points 606can then be used to define region 204, e.g., by considering points 606as a point-cloud or by reconstructing region 204 as a polygonal orcurvilinear mesh.

When the method finds more then one set of picture-elements in step 56,the loci of at least some of the sets are independently used to definean internal region associated with the respective set. The finalinternal region can then be defined, for example, by averaging theregions. The average can be weighted using the intensities associatedwith the sets as relative weights for the respective regions.Alternatively, the final region can be defined as the union of allregions. Still alternatively, the final region can be defined as theintersection of two or more regions.

According to a preferred embodiment of the present invention the methodloops back to step 54 in which one or more additional thermospatialimage is obtained, which additional thermospatial image corresponds to adifferent posture of the living body. Preferably, but not obligatorily,the additional thermospatial image is obtained such that the two or morethermospatial images alignable with respect to a predetermined fixedreference point on the body. The search for set(s) of picture-elementsand the definition of loci is preferably repeated for the additionalthermospatial image, so as to determine the location of the internalthree-dimensional thermally distinguishable region when the body is inthe second posture. The locations determined in the different posturescan then be compared to assess the accuracy of the procedure. A reportregarding the assessed accuracy can then be issued, e.g., on a displaydevice, a hard copy or the like.

Alternatively, the locations can be averaged and the average location ofthe internal three-dimensional thermally distinguishable region can bedisplayed or recorded on a tangible medium.

Once found, region 204 is preferably displayed or recorded on a tangiblemedium. Preferably, the method continues to step 62 in which a sourceregion 208 is located within region 204. The source region correspondsto the location of a thermally distinguished object within the body(e.g., an inflammation, a tumor) and can be located by any mathematicalprocedure known in the art, including, without limitation, a centroid, aweighted centroid and a center-of-mass of region 204.

Method 50 ends at step 64.

Following is a representative example of an algorithm for the definitionof loci and the determination of the internal region based on the loci,in the embodiment in which the distances d₁ and d₂ are geometricdistances and each locus is a plane.

A set of all pixels having similar intensity values from I−ΔI to I+ΔI isdenoted s. In Cartesian coordinate system, two pixels in s are denotedp₁=[x₁ y₁ z₁]^(T) and p₂=[x₂ y₂ z₂]^(T). The Euclidian norms of thesepixels are denoted ∥p₁∥² and ∥p₂∥², respectively. The locus of allpoints which are equidistant from p₁ and p₂ is a plane perpendicular tothe vector p₁−p₂=[x₁−x₂, y₁−y₂, z₁−z₂]^(T). The equation of such planeis:

$\begin{matrix}{{{2\left\lbrack {p_{1} - p_{2}} \right\rbrack}^{T} \cdot \begin{bmatrix}\begin{matrix}x \\y\end{matrix} \\z\end{bmatrix}} = {{p_{1}}^{2} - {{p_{2}}^{2}.}}} & \left( {{EQ}.\mspace{14mu} 2} \right)\end{matrix}$

which can also be written as:

2(x ₁ −x ₂)x+2(y ₁ −y ₂)y+2(z ₁ −z ₂)z=∥p ₁∥² −∥p ₂∥²  (EQ. 1)

The equations of all such planes are concatenated by the algorithm toprovide a linear least square problem:

$\begin{matrix}{{{A \cdot \begin{bmatrix}\begin{matrix}x \\y\end{matrix} \\z\end{bmatrix}} \approx b},} & \left( {{EQ}.\mspace{14mu} 3} \right)\end{matrix}$

where A and b are arrays which include all vectors 2(p_(i)−p_(j)) andall norm differences ∥p_(i)∥²−∥p_(j)∥², respectively, for any pair ofpixels p_(i), p_(j)εs. The solution of the linear least square problemis:

(A^(T)A)⁻¹A^(T)b.  (EQ. 4)

The algorithm is described by the following pseudo code:

1. Find the unique gray-level values on the surface.

2. Initialize A and b as an empty arrays.

3. For each gray-level:

-   -   (a) Find all the pixel pairs which share the same intensity        value (from I−ΔI to I+ΔI). Each pair defines a plane, which        consist of all the points with equal distances from the two        pixels of the pair. Construct the equation of the plane        (Equations 1 or 2).    -   (b) Discard all the pairs which are too close to each other.    -   (c) Concatenate the vector 2·(p₁−p₂) to array A.    -   (d) Concatenate the scalar ∥p₁∥²−∥p₂∥² to array b.

4. Solve the least square equation Ax≈b, (Equation 4).

5. End

The complexity of the problem is O(n²), where n is the size of s, bothfor selecting all pairs of s and for solving the corresponding leastsquare problem. For example, for a paraboloid of 41×41 pixels, theposition of the source was determined with an accuracy of (0.006, 0.006,0.009), and calculation time of 0.03 seconds on an IBM ThinkPad R50e,equipped with an Intel® Pentium®M 1.70 GHz processor and 599 MHz 504 Mbof RAM.

FIG. 7 is a schematic illustration of an apparatus 70 for determining aninternal three-dimensional thermally distinguishable region in theliving body, according to various exemplary embodiments of the presentinvention. Apparatus 70 can be used for executing one or more of themethod steps of method 50.

Apparatus 70 comprises input unit 42 for receiving the synthesizedthermospatial image, a searching unit 72 which searches over the gridfor one or more sets of picture-element represented by generally similarintensity values, a locus definition unit 74 which define the loci, anda region determination unit 76 for determining internal region 204three-dimensional thermally distinguishable region based on the loci asfurther detailed hereinabove. Apparatus 70 can also comprise sourceregion locator 48 as further detailed hereinabove.

Reference is now made to FIG. 8 which is a flowchart diagram of a method80 suitable for determining a number of thermally distinguishableobjects in the living body, according to various exemplary embodimentsof the present invention.

The method begins at step 82 and continues to step 84 in which asynthesized thermospatial image is obtained. The thermospatial image canbe generated by method 80 or it can be generated by another method orsystem from which the image can be read by method 80. It is appreciatedthat when thermal data are transformed to visible image, the image isgenerally in the form of isothermal contours. Broadly speaking, theisothermal contours can be closed or they can be open. For example, whenthe thermal data include temperature levels, the existence of closedisothermal contours typically indicates that the temperature has one ormore local extrema in the area surrounded by the closed contours, whilethe existence of open isothermal contours typically indicates that thetemperature is monotonic (including the case of a saddle point) in thearea of the open contours. For example, when a heat source is not withinthe field-of-view with the imaging device, the isothermal contours aregenerally open.

Representative examples of thermal data characterized by closedisothermal contours and open isothermal contours are provided in FIGS. 9a-b, respectively. As shown, in FIG. 9 a, the closed isothermal contourssurround at least one thermally distinguished spot 901, while no suchspot exists in FIG. 9 b where the isothermal contours are open.

In various exemplary embodiments of the invention, the thermal data ofthe thermospatial image obtained in step 84 is characterized by closedisothermal contours which surround at least one thermally distinguishedspot on the surface of the 3D spatial representation.

The method continues to step 86 in which the position and optionally thesize of one or more internal three-dimensional thermally distinguishableregions in the living body are determined. This can be done using method10, method 50 or any other method. Also contemplated is a combinationbetween methods (e.g., methods 10 and 50). Optionally and preferably,the method also determines one or more source regions as describedhereinabove.

Method 80 continues to step 88 in which the 3D spatial representation isanalyzed so as to define a boundary within the spatial representation.The boundary is defined such that points residing on one side of theboundary correspond to a single thermally distinguished spot on thesurface, while points residing on another side of the boundarycorrespond to a plurality of thermally distinguished spots on thesurface.

Step 88 may be better understood may with reference to FIGS. 10 a-d andthe following description.

FIG. 10 a is a schematic illustration of a thermospatial image withthermal data on surface 205 of 3D spatial representation 206. There aretwo thermally distinguished spots 901 and 902 on surface 205, each beingidentifiable as being surrounded by closed thermal contours. FIG. 10 bschematically illustrates a cross sectional view of 3D spatialrepresentation 206 corresponding to the thermospatial image of FIG. 10a. Shown in FIG. 10 b are spots 901 and 902 on surface 205 and aninternal thermally distinguished source point 903 in the bulk.

From the standpoint of a distance function D describing thermaldistances between source point 903 and various points on surface 205,spots 901 and 902 comprise local minima of D. That is to say, thethermal distance between source point 903 and spot 901 is smaller thanany thermal distance between source point 903 and points on surface 205in the immediate vicinity of spot 901; and the thermal distance betweensource point 903 and spot 902 is smaller than any thermal distancebetween source point 903 and points on surface 205 in the immediatevicinity of spot 902. Also shown in FIG. 10 b, is a surface point 904corresponding to global maximum.

A different situation is illustrated in FIGS. 10 c-d. FIG. 10 c is aschematic illustration of a thermospatial image (with closed thermalcontours) having a single thermally distinguished spot 905 on surface205. FIG. 10 d is a schematic illustration of a cross sectional view ofsurface 205, which correspond to the thermospatial image of FIG. 10 c.Shown in FIG. 10 b is spot 905 and source point 903 in the bulk. Fromthe standpoint of the distance function D, spot 905 is a local minimumof D. However, unlike the situation presented in FIGS. 10 a-b above,there is only one local minimum in FIGS. 10 c-d.

In principle, for a given surface 205 the number of local minima of thedistance function D depends on the position of source point 903 in thebulk. In various exemplary embodiments of the invention the methodanalyzes surface 205 and defines a boundary between all the possiblepositions of source point 903 for which D has a single minimum and allthe possible positions of source point 903 for which D has more than oneminimum. A representative illustration of such boundary is illustratedin FIG. 10 e, showing a boundary 906 which divides the bulk into twosections 907 and 908 whereby the lower section 907 includes all possiblepositions of source point 903 for which D has two minima and the uppersection 908 includes all possible positions of source point 903 forwhich D has a single minimum. Boundary 906 can be provided either in theform of a point-cloud or in a form of reconstructed surfaceapproximating the point-cloud. The point-cloud is illustrated in FIG. 10e as asterisks and the reconstructed surface is illustrated as a solidline.

Once boundary 906 is found, method 80 continues to step 90 in which theinternal region(s) and/or the source region(s) found in step 86 arecompared against boundary 906. Specifically, the method determines, foreach internal region, on which side of boundary 906 it resides. Suchcomparison allows method 80 to determine the number of thermallydistinguished objects in the living body, as will be understood from thefollowing simplified examples.

Hence, suppose that the thermospatial image obtained in step 84 includestwo thermally distinguished spots (cf. FIG. 10 a). Suppose further thatin step 86 the method identifies an internal source region locatedwithin section 908. Since it is expected that when a source region islocated in section 908 there will be only one thermally distinguishedspot on surface 205, the method can determine that the two thermallydistinguished spots on surface 205 correspond to two different thermallydistinguished objects in the bulk. On the other, if the thermospatialimage obtained in step 84 includes a single thermally distinguished spot(cf. FIG. 10 c), and the method identifies an internal source regionlocated within section 908, the method can determine that the identifiedinternal source region correspond to a single thermally distinguishedobject in the bulk with no other such objects. The comparison can alsoserve for estimating the accuracy of step 86. For example, suppose thatthe thermospatial image obtained in step 84 includes one thermallydistinguished spot (cf. FIG. 10 c), and that in step 86 the methodidentifies an internal source region located within section 907. Sinceit is expected that when a source region is located in section 907 therewill be two thermally distinguished spots on surface 205, the method candetermine that the accuracy of the procedure performed in step 86 isinsufficient and issue a report or signal the operator regarding suchinaccuracy. Alternatively or additionally, the method can loop back tostep 86 and determine the position and/or size of the source regionusing another procedure or using the same procedure but with increasedaccuracy (e.g., using more sampled points for the reconstruction of the3D spatial representation 206).

Method 80 ends at step 92.

FIG. 11 is a schematic illustration of an apparatus 110 for determininga number of thermally distinguishable objects in the living body,according to various exemplary embodiments of the present invention.Apparatus 110 can be used for executing one or more of the method stepsof method 80.

Apparatus 110 comprises input unit 42 for receiving the synthesizedthermospatial image and a region determination unit 112 which determinesthe internal 3D thermally distinguishable region and optimally theinternal source region. Unit 112 may comprise selected components ofapparatus 40 (e.g., unit 44, calculator 46, unit 46, locator 48) and/orapparatus 70 (e.g., unit 72, unit 74, unit 76) and may perform selectedsteps of method 10, method 50 or combination thereof. Apparatus 110 mayalso receive the internal region(s) from apparatus 40 or 70.

Apparatus 110 further comprises an analyzer 114 which analyzes the 3Dspatial representation and defines boundary 906 as described above, anda comparison unit 116 which compares the internal 3D thermallydistinguishable region with boundary 906 so as to determine the numberof thermally distinguishable objects in the living body as furtherdetailed hereinabove.

The following description is of techniques for obtaining thethermospatial images, according to various exemplary embodiments of thepresent invention. The techniques described below can be employed by anyof the method and apparatus described above.

A thermospatial image can be generated obtained by acquiring one or morethermographic images and mapping the thermographic image(s) on a 3Dspatial representation.

Reference is now made to FIG. 12 a which is a schematic illustration ofa thermospatial imaging system 120 in accordance with preferredembodiments of the present invention. As shown in FIG. 12 a, a livingbody 210 or a part thereof of a person 212 is located in front of animaging device 214. The person 212, may be standing, sitting or in anyother suitable position relative to imaging device 214. Person 212 mayinitially be positioned or later be repositioned relative to imagingdevice 214 by positioning device 215, which typically comprises aplatform moving on a rail, by force of an engine, or by any othersuitable force. Additionally, a thermally distinguishable object 216,such as a tumor, may exist in body 210 of person 212. For example, whenbody 210 comprises a breast, object 216 can be a breast tumor such as acancerous tumor.

In accordance with a preferred embodiment of the present invention,person 212 may be wearing a clothing garment 218, such as a shirt.Preferably, clothing garment 218 may be non-penetrable or partiallypenetrable to visible wavelengths such as 400-700 nanometers, and may bepenetrable to wavelengths that are longer than visible wavelengths, suchas infrared wavelengths. Additionally, a reference mark 220 may belocated close to person 212, preferably directly on the body of person212 and in close proximity to body 210. Optionally and preferably,reference mark 220 is directly attached to body 210. Reference mark 220may typically comprise a piece of material, a mark drawn on person 212or any other suitable mark, as described herein below.

Imaging device 214 typically comprises at least one visible lightimaging device 222 that can sense at least visible wavelengths and atleast one thermographic imaging device 224 which is sensitive toinfrared wavelengths, typically in the range of as 3-5 micrometer and/or8-12 micrometer. Typically imaging devices 222 and 224 are capable ofsensing reference mark 220 described hereinabove.

Optionally, a polarizer 225 may be placed in front of visible lightimaging device 222. As a further alternative, a color filter 226, whichmay block at least a portion of the visible wavelengths, may be placedin front of visible light imaging device 222.

Typically, at least one visible light imaging device 222 may comprise ablack-and-white or color stills imaging device, or a digital imagingdevice such as CCD or CMOS. Additionally, at least one visible lightimaging device 222 may comprise a plurality of imaging elements, each ofwhich may be a three-dimensional imaging element.

Optionally and preferably, imaging device 214 may be repositionedrelative to person 212 by positioning device 227. As a furtheralternative, each of imaging devices 222 and 224 may also berepositioned relative to person 212 by at least one positioning device228. Positioning device 227 may comprise an engine, a lever or any othersuitable force, and may also comprise a rail for moving imaging device214 thereon. Preferably, repositioning device 228 may be similarlystructured.

Data acquired by visible light imaging device 222 and thermographicimaging device 224 is output to a data processor 230 via acommunications network 232, and is typically analyzed and processed byan algorithm running on the data processor. The resulting data may bedisplayed on at least one display device 234, which is preferablyconnected to data processor 230 via a communications network 236. Dataprocessor 230 typically comprises a PC, a PDA or any other suitable dataprocessor. Communications networks 232 and 236 typically comprise aphysical communications network such as an internet or intranet, or mayalternatively comprise a wireless network such as a cellular network,infrared communication network, a radio frequency (RF) communicationsnetwork, a blue-tooth (BT) communications network or any other suitablecommunications network.

In accordance with a preferred embodiment of the present inventiondisplay 234 typically comprises a screen, such as an LCD screen, a CRTscreen or a plasma screen. As a further alternative display 234 maycomprise at least one visualizing device comprising two LCDs or twoCRTs, located in front of a user's eyes and packaged in a structuresimilar to that of eye-glasses. Preferably, display 234 also displays apointer 238, which is typically movable along the X, Y and Z axes of thedisplayed model and may be used to point to different locations orelements in the displayed data.

Reference is now made to FIGS. 12 b-f and 13 a-e which illustrate thevarious operation principles of thermospatial imaging system 120, inaccordance with various exemplary embodiments of the invention.

The visible light imaging is described first, with reference to FIGS. 12b-f, and the thermographic imaging is described hereinafter, withreference to FIGS. 13 a-e. It will be appreciated that the visible lightimage data acquisition described in FIGS. 12 b-f may be performedbefore, after or concurrently with the thermographic image dataacquisition described in FIGS. 13 a-e.

Referring to FIGS. 12 b-f, person 212 comprising body 210 is located onpositioning device 215 in front of imaging device 214, in a firstposition 240 relative to the imaging device. First image data of body210 is acquired by visible light imaging device 222, optionally throughpolarizer 225 or as an alternative option through color filter 226. Theadvantage of using a color filter is that it can improve thesignal-to-noise ratio, for example, when the person is illuminated witha pattern or mark of specific color, the color filter can be used totransmit only the specific color thereby reducing background readings.Additionally, at least second image data of body 210 is acquired byvisible light imaging device 222, such that body 210 is positioned in atleast a second position 242 relative to imaging device 214. Thus, thefirst, second and optionally more image data are acquired from at leasttwo different viewpoint of the imaging device relative to body 210.

The second relative position 242 may be configured by repositioningperson 212 using positioning device 215 as seen in FIG. 12 b, byrepositioning imaging device 214 using positioning device 227 as seen inFIG. 12 c or by repositioning imaging device 222 using positioningdevice 228 as seen in FIG. 12 d. As a further alternative, secondrelative position 242 may be configured by using two separate imagingdevices 214 as seen in FIG. 12 e or two separate visible light imagingdevice 222 as seen in FIG. 12 f.

Referring to FIGS. 13 a-e, person 212 comprising body 210 is located onpositioning device 215 in front of imaging device 214, in a firstposition 244 relative to the imaging device. First thermographic imagedata of body 210 is acquired by thermographic imaging device 224.Optionally and preferably at least second thermographic image data ofbody 210 is acquired by thermographic imaging device 224, such that body210 is positioned in at least a second position 242 relative to imagingdevice 214. Thus, the first, second and optionally more thermographicimage data are acquired from at least two different viewpoints of thethermographic imaging device relative to body 210.

The second relative position 246 may be configured by repositioningperson 212 using positioning device 215 as seen in FIG. 13 a, byrepositioning imaging device 214 using positioning device 227 as seen inFIG. 13 b, or by repositioning thermographic imaging device 224 usingpositioning device 228 as seen in FIG. 13 c. As a further alternative,the second relative position 246 may be configured by using two separateimaging devices 214 as seen in FIG. 13 d or two separate thermographicimaging devices 224 as seen in FIG. 13 e.

Image data of body 210 may be acquired by thermographic imaging device224, by separately imaging a plurality of narrow strips of the completeimage of body 210. Alternatively, the complete image of body 210 isacquired by the thermographic imaging device, and the image is sampledin a plurality of narrow strips or otherwise shaped portions forprocessing. As a further alternative, the imaging of body 210 may beperformed using different exposure times.

The thermographic and visible light image data obtained from imagingdevice 214 is preferably analyzed and processed by data processor 230 asfollows. Image data acquired from imaging device 222 is processed bydata processor 230 to build a three-dimensional spatial representationof body 210, using algorithms and methods that are well known in theart, such as the method described in U.S. Pat. No. 6,442,419 which ishereby incorporated by reference as if fully set forth herein. The 3Dspatial representation preferably comprises the location of referencemarker 220 (cf. FIG. 1 a). Optionally and preferably, the 3D spatialrepresentation comprises information relating to the color, hue andtissue texture of body 210. Thermographic image data acquired fromimaging device 224 is processed by data processor 230 to build athermographic three-dimensional model of body 210, using algorithms andmethods that are well known in the art, such as the method described inU.S. Pat. No. 6,442,419. The thermographic 3D model preferably comprisesreference marker 220 (cf. FIG. 1 b). The thermographic 3D model is thenmapped by processor 230 onto the 3D spatial representation, e.g., byaligning reference marker 220, to form the thermospatial image.

The combination of two or more visible light images to construct the 3Dspatial representation of body 210, and the combination of two or morethermographic images to construct the thermographic 3D model, mayrequire regionwise comparison between image data (either in visiblelight or thermographic) acquired from different viewpoints. Suchcomparison is typically a twofold process: firstly, selected groups ofpicture-elements are identified in each individual image, and secondlythe identified groups of picture-elements of one image are matched amongthe various images. The present embodiments successfully provide amethod suitable for improving the identification and matching processes.

According to a preferred embodiment of the present invention the body isilluminated with a series of spots, where at least one spot of theseries is distinguishable from all other spots. A representative exampleof such series is illustrated in FIG. 14 showing a series 142 of spots,in which one spot 144 (the third from left, in the present example) isdistinguished from all other spots. In the representative example ofFIG. 14, series 142 is a row of spots, but it is to be understood thatthe series can have any geometrical property, either one-dimensional(e.g., a row, a column, an arc, a curvilinear line, etc.), ortwo-dimensional (e.g., a matrix). Spot 144 can be distinguished by anydistinguishing feature, include, without limitation, shape, size,wavelength, intensity and orientation.

Once the body is illuminated with the series, one or more imagingdevices are preferably used for acquiring two or more images of the bodyand the series from at least two different viewpoints. The images can bevisible light images acquired using one or more visible light imagingdevices, or thermographic images acquired using one or morethermographic imaging devices. The wavelength or range of wavelengths ofseries 142 is compatible with the range of wavelengths to which theimaging device is sensitive. Thus, for visible light image, series 142is generally illuminated at the visible range of wavelengths, and forthermographic image, series 142 is generally illuminated at the infraredrange of wavelengths.

Once the images are acquired, the distinguishable spot 144 is preferablyidentified and used for identifying all other spots in series. Withreference to the exemplified series of FIG. 14, knowing the number ofspots in the series and the relative position of spot 144 in the series(third from the left in the present example) all other spots can beidentified by their relative position with respect to spot 144. Thus,the method can scan across all picture-elements along a line of theimage and counts the spots beginning with the already identified spot.

Thus, the present embodiments use spot 144 as a pointer for indexing allthe spots in series 142. Such indexing greatly enhances the efficiencyof the matching step, because it allows the matching at series level asopposed to spotwise matching. Since the series can in principle be ofany length, a single series matching can encompass large portion of theimages.

The matching enables the calculations of range data for at least somespots, more preferably for each spot in the series, typically bytriangulation. The 3D spatial representation or the 3D thermographicmodel can then be built using the range data.

According to another embodiment of the present invention, theidentification and matching of points is performed for a small number ofilluminated spots, e.g., 5 spots, more preferably 4 spots, morepreferably 3 spots, more preferably 2 spots, more preferably a singlespot. In this embodiment, a plurality of images is acquired from eachview point, where each such acquisition is preceded with an illuminationof a different region or location on the body's surface with spots. Theidentification and matching of the spots is performed separately foreach such region or location.

In any of the above embodiments, identification of the spots can berealized by subtraction. More specifically, each image is acquiredtwice: one time without illuminating the body with spots and anothertime with the spots. The image acquired without spots is then subtractedfrom the image acquired with the spots, and the remaining data includemostly information regarding the spots with minimal or no backgroundnoise.

It is appreciated that range imaging systems and thermospatial imagingsystems, such as system 120 above or other systems as further describedbelow, may require a calibration step before the acquisition.

The present embodiments successfully provide a calibration procedurewhich employs a database of figures having a plurality of entries, eachhaving a figure entry and an angle entry corresponding to a viewpoint ofthe figure entry. The database is typically prepared in advance byprojecting figures, which can be, e.g., geometrical figures, on asurface from a plurality of different view points and determining thedistortion caused to each figure for each viewpoint. Each distortedfigure is recorded as a figure-entry and each viewpoint is recorded asan angle entry of the database. The calibration is preferably performedas follows. The body is illuminated with a figure and at least twoimages of the body and the figure are acquired from at least twodifferent viewpoints. For each image, the acquired figure is identified.The database is accessed and searching over database for a figure entrywhich is generally similar to the identified figure of the respectiveimage. Once the figure entries are found for all images, the respectiveangle entries are used for calculating range data by triangulation. Theadvantage of the calibration procedure of the present embodiments isthat the search over the database can, in principle, be faster than acomplete calculation of the angles.

Calibration of a thermospatial imaging system according to variousexemplary embodiments of the present invention can also be done byilluminating the body with a pattern in a plurality of wavelengths,where at least one wavelength is detectable by the thermographic imagingdevice of the system and at least one wavelength is detectable by thevisible light imaging device of the system. Illuminating devices capableof providing such illumination are known in the art. For example, aninfrared lamp such as one of the IR-50 series, which is commerciallyavailable from Scitec Instruments Ltd, UK, can be employed. Using thethermographic and visible light imaging devices a thermographic imageand a visible light image of the body are acquired. The calibration isperformed by aligning the pattern as acquired by the visible lightimaging device with the pattern as acquired by the thermographic imagingdevice. According to a preferred embodiment of the present invention thethermographic and visible light images are acquired substantiallysimultaneously, such that the body is essentially static during thecalibration.

The identification of the pattern can optionally and preferably byemploying the indexing technique as further detailed hereinabove withreference to FIG. 14.

Reference is now made to FIG. 15 which is a flowchart diagram of amethod 150 suitable for constructing a 3D spatial representation of abody, according to various exemplary embodiments of the presentinvention. In various exemplary embodiments of the invention method 150constructs the 3D spatial representation based on thermographic imagesand preferably without using visible light images.

Method 150 begins at step 152 and continues to step 154 in which thebody is illuminated with a pattern, e.g., a coded pattern in theinfrared range. The pattern can be in any shape which allows theidentification thereof. For example, in one embodiment the patterncomprises one or more bar codes, in another embodiment, the patterncomprises a series of spots such as series 144 described above, in afurther embodiment, the pattern comprises a combination of bar cods anda series of spots.

Typically the pattern is illuminated using a laser light with wavelengthof 3-14 micrometer. According to a preferred embodiment of the presentinvention a CO₂ laser with wavelength of 10.6 micrometer is employed.Alternatively, an infrared lamp such as one of the IR-50 series, whichis commercially available from Scitec Instruments Ltd, UK, can beemployed. The pattern is selected in accordance with the desiredtechnique which is used to construct the three-dimensional spatialrepresentation. Thus, the pattern can be selected to allow temporalcoding and/or spatial coding.

Preferably, the pattern projected on the body varies with time. Forexample, a series of patterns can be projected, one pattern at a time,in a rapid and periodic manner. This can be done in any of a number ofways. For example, a plate having a periodically varying transmissioncoefficient can be moved in front of an illuminating device.Alternatively, a disk having a circumferentially varying transmissioncoefficient can be rotated in front of the illuminating device. Stillalternatively, strobing technique can be employed to rapidly project aseries of stationary patterns, phase shifted with respect to each other.Also contemplated is the use of optical diffractive elements for formingthe pattern. The pattern can also be in the form of a series of spots,as further detailed hereinabove (cf. FIG. 14 and the accompanyingdescription). A preferred illuminating device for providing a pattern isdescribed hereinunder.

In various exemplary embodiments of the invention the illumination ischaracterized by sufficiently short pulse length. Preferably pulsesshorter than 20 milliseconds, e.g., 15 milliseconds or less, morepreferably 10 milliseconds or less, are employed.

Method 150 continues to step 156 in which one or more thermographicimaging device is used for acquiring one or more thermographic images ofthe body and the pattern. The thermographic imaging device is preferablyequipped with a suitable optics for acquiring data in the infrared rangefrom the body and the pattern. Such optics is commercially availablefrom, e.g., Holo-Or Ltd, Israel. In various exemplary embodiments of theinvention the method acquires two or more thermographic images of thebody and the pattern from two or more different viewpoints. Thethermographic imaging is performed in accordance with the type ofpattern which is selected. For example, when temporal coding isemployed, the thermographic imaging device is synchronized with thepulses of the illumination.

According to a preferred embodiment of the present invention theexposure times of the thermographic imaging device are of less than 20milliseconds. Preferably, the exposure time and the readout time of thethermographic imaging device complement to 20 milliseconds for eachcycle. For example, in one embodiment the exposure time is 19milliseconds and the readout is during 1 millisecond. This embodiment isillustrated in FIG. 16 a.

In an alternative embodiment, several readouts are executedsimultaneously with one exposure. In this embodiment, the exposure timecan be of 20 milliseconds or less. This embodiment is illustrated inFIG. 16 b. According to a preferred embodiment of to the presentinvention the readouts are executed accumulatively. This can be done,for example, by accumulating the acquired signal to previously storedsignal in the imaging device's pixel without erasing or overwritten theprevious signal. After several readouts, say every 20 milliseconds, thedata stored in the imaging device's pixel can be erased. Alternatively,the accumulation can be performed digitally.

In an alternative embodiment, both the exposure time and readout timeare shorter than 20 milliseconds. This embodiment is illustrated in FIG.16 c.

According to a preferred embodiment of the present invention the methodproceeds to step 158 in which image data originating from heat generatedby the body is filtered out from the acquired thermographic image. Thiscan be done by processing the thermographic image(s), e.g., usingdigital intensity filters. Alternatively, one or more thermographicimages of the body are acquired without the pattern, and the filtrationis achieved by subtracting the thermographic images acquired without thepattern from thermographic images acquired with the pattern.

The method continues to step 160 in which range data corresponding topattern are calculated. The range data can be calculated bytime-of-flight technique, triangulation or any technique known in theart, to this end see, e.g., S. Inokuchi, K. Sato, and F. Matsuda, “Rangeimaging system for 3D object recognition”, in Proceedings of theInternational Conference on Pattern Recognition, pages 806-808, 1984;and U.S. Pat. Nos. 4,488,172, 4,979,815, 5,110,203, 5,703,677,5,838,428, 6,349,174, 6,421,132, 6,456,793, 6,507,706, 6,584,283,6,823,076, 6,856,382, 6,925,195 and 7,194,112.

The method continues to step 162 in which the thermographic image andthe range data are used for constructing the 3D spatial representationof the body.

Once constructed, the 3D spatial representation can be displayed in avisible form, e.g., using a display device or a printer, or it can bedigitally recorded on a computer readable medium. The 3D spatialrepresentation can also be outputted, e.g., digitally, to another systemor apparatus which is configured to receive the 3D spatialrepresentation and analyze and/or process it. For example, the 3Dspatial representation can be outputted to a system or apparatus whichgenerates a thermospatial image. The method ends at step 164.

FIG. 17 is a schematic illustration of a system 170 for constructing athree-dimensional spatial representation of a body. System 170 can beused for executing method 150 or selected steps thereof. System 170comprises an illuminating device 172, which is designed and constructedto illuminate the body 210 with a pattern 174 in the infrared range.Pattern 174 is illustrated as a bar code, this need not necessarily bethe case, since, for some applications, it may not be necessary for thepattern to be in the form of a bar code. Thus, pattern 174 can be of anyshape and texture. Further, although the a single pattern is shown inFIG. 17, this need not necessarily be the case since device 172 can beconfigured to illuminate body 210 by more than one pattern. Thus, thepresent embodiments also contemplate a series of patterns. In preferredembodiment of the invention pattern 174 comprises at least in partseries 142 so as to allow indexing as further detailed hereinabove.

Device 172 can comprise a laser device, an infrared lamp, or any otherilluminating device capable of providing light in the infrared range andoptionally also in the visible range as described above. System 170further comprises one or more thermographic imaging devices 224 whichacquire one or more thermographic images of body 210 and pattern 174.Preferably, thermographic imaging devices 224 acquire at least twoimages from at least two different viewpoints. System 170 furthercomprises a data processor 230 which calculates range data correspondingto pattern, and constructs the 3D spatial representation of body 210 asfurther detailed hereinabove. In various exemplary embodiments of theinvention processor 230 filters out image data originating from heatgenerated by the body, e.g., by subtracting thermographic imagesacquired without pattern 174 from thermographic images acquired withpattern 174 as further detailed hereinabove.

The techniques of the present embodiments can be utilized for obtainingand/or analyzing thermospatial images of portions of external as well asinternal organs of the body. The techniques of the present embodimentscan also be employed during open surgery in which case the organ to bethermospatially imaged can be accessed using the thermospatial system.Thermospatial systems most suitable for open surgery applicationsaccording to preferred embodiments of the present invention are similarto the system described above, but preferably with miniaturized imagingdevices to allow easy access to the internal organs. This embodiment isparticularly useful for imaging internal organs which are bothaccessible and movable by the surgeon during open surgery.

In cases of tumors in the liver (adenomas, hepatoma, etc.), for example,during open surgery, the surgeon positions the imaging devices near theliver and acquires the thermospatial image of the liver to determinelocations of pathologies such as tumors therein. Once the location(s)are determined, the surgeon can destroy the tumor, e.g., by ablation orcavitation. It is recognized that as the liver is an extremely bloodyorgan, the ability of destroying tumors in the liver without invadingthe liver's tissue is of utmost importance. Furthermore, in extremecases, a portion of the liver containing an untreatable amount of tumorscan be removed, while the remaining portion which contains fewer tumors(e.g., metastases) can be thermospatially imaged and the tumors thereincan be destroyed by ablation or cavitation. The above procedure can beperformed also for other organs such as a kidney, colon, stomach orpancreas.

Another organ which can be imaged in various exemplary embodiments ofthe invention is the brain. The brain can contain many types of tumorswhich can be located and optionally diagnosed, according to the teachingof the present embodiments. Representative examples of such tumorsinclude, without limitation, primary benign tumors such as meningioma,primary malignant tumors such as glyoblastoma or astrocytoma, and anymalignant metastasis to the brain from any organ such as colon, breast,testis and the like.

This can be achieved, for example, during open brain surgery. In thisembodiment, a portion of the cranium is removed and the imaging devicesof the thermospatial are inserted in a predetermined arrangement,between the brain and the remaining portion of the cranium. Athermospatial image of the brain can then be generated as furtherdetailed hereinabove. If the brain contains pathologies such as tumors,the pathologies can be destroyed or at least partially damaged, forexample, by ablation or cavitation.

The technique of the present embodiments can also be employed inminimally invasive procedures. To this end the present Inventorcontemplates a thermospatial imaging system generally referred to hereinas system 180 and schematically illustrated in FIGS. 18 a-c.

Referring to FIGS. 18 a-c, system 180 comprises, in its simplestconfiguration, an intracorporeal probe system 182 having therein one ormore thermographic imaging devices 184 for acquiring at least onethermographic image of the anterior of the living body.

Intracorporeal probe system 182 is preferably inserted endoscopically bymounting the device on a suitable transport mechanism, such as, but notlimited to, an endoscopic probe or a catheter. Intracorporeal probesystem 182 is preferably flexible so as to facilitate its endoscopicinsertion. Additionally and preferably intracorporeal probe system 182is sizewise and geometrically compatible with the internal cavities ofthe subject so as to minimize discomfort of the subject during thenon-invasive in vivo examination. Thus, intracorporeal probe system 182is preferably adapted for transrectal, transurethral, transvaginal ortransesophageal examination

Imaging device 184 is preferably a miniature imaging device to allowmounting it on probe system 182. System 180 further comprises dataprocessor 230 which communicates with probe system 182, for example, viawireless communication system having a first transmitter/receiver 186 onprobe system 182 and a second transmitter/receiver 188 on processor 230.Alternatively, communication can be established via a communication line190. Image data acquired by imaging device 184 is transmitted via probesystem 182 to processor 230 which receives the image data and analyzesit to provide and display a synthesized thermospatial image of theanterior of the living body. The generation of thermospatial image is,as stated by mapping one or more thermographic images onto surface 205of 3D spatial representation 206.

In various exemplary embodiments of the invention probe system 182further comprises one or more visible light imaging devices 192 whichacquire at least one visible light image of the anterior of the livingbody and transmits image data pertaining to the visible light image viaprobe system 182 to processor 230. In this embodiment, processor 230uses the visible light image data for constructing the 3D spatialrepresentation.

Alternatively, as illustrated in FIG. 18 b, system 180 comprises twointracorporeal probe systems, designated 182 and 182′, wherethermographic imaging device(s) 184 is mounted on probe system 182 andvisible light imaging device(s) 192 is mounted on probe system 182′. Inthis embodiment, probe systems 182 and 182′ preferably communicatethereamongst, via transmitter/receiver 186 or communication line 190,for example, to allow synchronization.

In yet another alternative, as illustrated in FIG. 18 c, system 180comprises two intracorporeal probe systems, 182 and 182′ each havingboth thermographic 184 and visible light 192 imaging device(s).Similarly to the embodiment in FIG. 18 b, probe systems 182 and 182′preferably communicate thereamongst.

In various exemplary embodiments of the invention system 180 furthercomprises an, illuminating device 194 for illuminating the anterior ofthe body with a pattern. The pattern serves for the calculation of rangedata as further detailed herein above. Illuminating device 194 ispreferably mounted on probe system 182

Generally, system 180 can be employed in many minimally invasiveprocedures, including, without limitation, Arthroscopy, Bronchoscopy,Colonoscopy, Colposcopy, Cystoscopy, Endoscopic Biopsy, Gastroscopy,Laparscopy, Laryngoscopy, Proctoscopy, Thoracocopy,Esophogeal-gastro-duodensoscopy, and endoscopic retrogradecholangio-pancreatography.

Reference is now made to FIG. 19 a, which is a schematic illustration ofan embodiment in which the intracorporeal probe system is used forthermospatially imaging the stomach. Shown in FIG. 19 a is the esophagus360 and the stomach 361 (image source: National Library of Medicine(NLM) web site). Also shown is the intracorporeal probe system 182,inserted through esophagus 360 by a catheter 363 and positioned instomach 361. This embodiment can be used for imaging benign tumors suchas Leomyoma, or malignant tumors such as carcinoma or lymphoma.

The ability to insert the intracorporeal probe system 182 through theesophagus allows the operator to obtain thermospatial images of theesophagus itself, thereby to locate pathologies, such as the carcinomaof the esophagus, thereon.

Reference is now made to FIG. 19 b, which is a schematic illustration ofan embodiment in which intracorporeal probe system 182 is used forthermospatially imaging the prostate or bladder. Shown in FIG. 19 b arethe rectum 367, the bladder 366, the prostate 370 and the urethra 369.In the present embodiments, intracorporeal probe system 182 can beinserted into through the anus 368 into the rectum 367, or through theurethra 369. When device probe system 182 is inserted through theurethra it can be used for imaging the prostate, in which case probesystem 182 is positioned near the prostate, or the bladder, in whichcase probe system 182 is inserted into the bladder as shown in FIG. 19b.

Reference is now made to FIG. 19 c, which is a schematic illustration ofan embodiment in which probe system 182 is used for thermospatiallyimaging the uterus, bladder or ovary. Shown in FIG. 19 c are the rectum367, the bladder 366, the uterus 372 and the ovary 373. In the presentembodiments, probe system 182 can be inserted through the vagina 374.Probe system 182 can alternatively be mounted on a catheter and insertedinto the uterus. The thermospatial imaging of this embodiment can beused for locating or diagnosing polyps in the uterus or bladder.Additionally this embodiment can be used for locating and optionallydiagnosing benign tumors in the uterus (e.g., myomas) or any malignanttumors therein. For the ovary, this embodiment can be used forthermospatially imaging any primary or secondary malignant tumorstherein.

In various exemplary embodiments of the invention two or more 3D spatialrepresentations are constructed, such that different spatialrepresentations correspond to different postures of the subject. Theseembodiments are applicable for any type of thermospatial imagingdescribed above.

At least a few of these 3D spatial representations are optionally andpreferably may accompanied by the acquisition of one or morethermographic image for the respective posture, and the mapping of therespective thermographic image on the respective 3D spatialrepresentations, such as to provide a plurality of thermospatial images.

One advantageous of several 3D spatial representations is that it can beused by the method of the present embodiments as a consistency test.This is illustrated in FIG. 20 which is a flowchart diagram of a method400 suitable for assessing the accuracy of the determination of theinternal thermally distinguished regions in the body.

Method 400 begins at step 402 and continues to step 404 in which asynthesized thermospatial image is obtained. The thermospatial image canbe generated by method 400 or it can be generated by another method orsystem from which the image can be read by method 400. The methodcontinues to step 406 in which the position and optionally the size ofone or more internal three-dimensional thermally distinguishable regionsin the living body are determined. This can be done using method 10,method 50 or any other method, including combination between differentmethods (e.g., methods 10 and 50). Optionally and preferably, the methodalso determines one or more source regions as described hereinabove.

Method 400 continues to step 408 in which one or more additional 3Dspatial representations of the living body are obtained, where each 3Dspatial representation corresponds to a different viewpoint with respectto the living body and/or a different posture of the living body. Method400 can construct the additional 3D spatial representations or they canbe constructed by another method or system from which they can be readby method 400.

Method 400 continues to step 410 in which, based on the internalthree-dimensional thermally distinguishable region, the expectedtopology of isothermal contours on the surface the additional 3D spatialrepresentation is constructed for at least a few of the 3D spatialrepresentations. The expected topology preferably includes informationregarding the general shape of the contours (closed, open), but it canalso include more information, e.g., temperature data on the surface,and the like. The expected topology can be calculated numerically usingthe position of the internal region in the body, the shape of the 3Dspatial representation, and by modeling the thermal conductivity of thebody which can be, either isotropic or non-isotropic. For example, themethod can construct the expected topology by considering the thermaldistance function D as further detailed hereinabove, see FIGS. 10 a-eand the accompanying description.

Method 400 continues to step 412 in which one or more additionalthermospatial image are obtained, where each thermospatial imagecorresponds to a different viewpoint with respect to the living bodyand/or a different posture of the living body. The thermospatial imagescan be generated by method 400 or they can be generated by anothermethod or system from which the image can be read by method 400. Themethod continues to step 414 in which the additional thermospatialimage(s) are compared to the expected topologies. If the topology of theisothermal contours in an additional thermospatial image is similar tothe expected topology, the method can determine that the position andoptionally size of the internal region is accurate. Otherwise, themethod identifies an error determines that an error has been can Thus,method 400 serves as a consistency check, and determine whether or notthere is a consistency with respect to the location of the thermallydistinguished object within the body.

Method 400 continues to step 418 in which a report relating to thecomparison is issued, and ends at step 419.

An additional advantageous of several 3D spatial representations is thatthey can serve in preliminary tests to select the proper viewpoint forthe imaging and/or the posture of the body. Specifically, for at least afew 3D spatial representations, the expected topology of the isothermalcontours on the surface is preferably constructed. Once two or more suchexpected topologies are known, the operator or physician can select theviewpoint for the imaging and/or the posture of the body which is mostsuitable for the examination.

For example, suppose that the living body is the breast of a woman, andthat a 3D spatial representation is obtained when the woman is standingand a second 3D spatial representation is obtained when the woman bendsforwards. Suppose further that for the first 3D spatial representationthe expected topology is of open isothermal contours, and that for thesecond 3D spatial representation the expected topology is of closedisothermal contours. In this case, the operator or physician may decideto select the second posture (bending forward) because the determinationof the position of a thermally distinguishable object is more accuratewhen the thermal data is characterized by closed isothermal contours.

It is preferred that the thermospatial imaging will be performed whenthere are minimal thermal changes in the body of the subject during theacquisition of thermographic images.

Reference is now made to FIG. 21 which is a flowchart diagram of amethod 420 suitable for ensuring that a living body is at a generallystable thermal condition, according to various exemplary embodiments ofthe present invention. The method begins at step 422 and continues tostep 424 in which a series of thermographic images of the living bodyare acquired from a predetermined viewpoint. Method 420 continues tostep 426 in which the thermographic images are compared so as to extractthermal changes in the images. In various exemplary embodiments of theinvention steps 424 and step 426 are performed substantiallycontemporaneously.

The comparison can be done in more than one way. In one embodiment, eachthermographic image is compared to a single previously acquiredthermographic image. Alternatively, at least a few thermographic imagesare compared to a plurality of, e.g., all the previously acquiredthermographic images. Optionally and preferably the method continues tostep 427 in which the thermal changes are displayed on a display device.

The method continues to decision step 428 in which the method determineswhether the thermal changes are below a predetermined threshold. If thechanges are not below the threshold, the method loops back to step 424.If the changes are not below the threshold the method continues to step430 in which a report indicating that the living body is at a generallystable thermal condition is issued. The value of the threshold dependson the thermal imaging device and is typically set to the thermalresolution thereof. Known in the art are thermal imaging devices with aresolution of 0.1° C. and below. For example, the Photon OEM Camera coreis commercially available from FLIR and provides thermal resolution ofless than 0.085 degrees centigrade, TH9100PMV is commercially availablefrom NEC and provides thermal resolution of less than 0.06 degreescentigrade, and IVN 3200-HS is commercially available from IMPAC andprovides resolution of less than 0.08 degrees centigrade. Thus,according to a preferred embodiment of the present invention the valueof the threshold is about 0.1 degrees centigrade.

The present embodiments can also be used for monitoring the position ofa medical device, such as a biopsy needle or a catheter in the livingbody. For example, when a biopsy needle is to be introduced into atumor, thermospatial imaging can be used to ensure that the path of theneedle is appropriate for performing the biopsy. Furthermore, sincethermospatial imaging can be used, as stated, for determining theposition and optionally size of a tumor, a combined procedure can beemployed whereby the same thermospatial imaging system is used fordetermining the presence, position and optionally size of the tamer andfor monitoring the path of the biopsy needle once introduced into thebody.

In various exemplary embodiments of the invention the temperature of themedical device (needle, catheter, etc.) is set to a temperature which issufficiently different from the average temperature of the body. Thisensures that the medical device is detectable by the thermospatialimaging system. Once the temperature of the medical device is set, themedical device is introduced into the body. One or more synthesizedthermospatial images of the body and the medical device can then begenerated and used for monitoring the position or path of the device.

Reference is now made to FIG. 22 which is a schematic illustration ofmedical device 440 insertable into a living body. Device 440 can beused, for example, as a biopsy device, e.g., for performing standardbreast biopsy procedures. A particular advantage of device 440 is thatit allows to sense or measure temperature while being inserted into thebody. Device 440 is preferably relatively small in size and does notproduce a level of thermal conductivity that would affect the sensingmade thereby.

Preferably, device 440 is capable of detecting and providing a profileof temperatures of the tumor and surrounding tissue with high accuracy,so as to enable the diagnosis of cancer at an early stage when the tumoris small in size.

Device 440 preferably comprises a hollow structure 442 having a proximalend 444, a distal end 446 and an optical fiber 448 extending from end444 to end 446. Distal end 446 can be shaped as a tip so as to allowdevice 440 to be easily inserted into the body. Fiber 448 is designedand constructed to transmit thermal radiation from distal end 446 toproximal end 444. The thermal radiation can be measured or recorded by asuitable device, such as, but not limited to, a thermal imaging device450 which optically communicates with fiber 448. Fiber 448 is made of amaterial suitable for guiding electromagnetic radiation in the infraredrange. Fiber 448 can be made of a material which is different from thematerial of structure 442. In this embodiment, fiber 448 is introducedinto a passageway 452 in structure 442. Alternatively, structure 442 canbe made material suitable for guiding electromagnetic radiation in theinfrared range in which case the passageway itself can serve as anoptical fiber.

It is appreciated that in the embodiment illustrated in FIG. 22, nomeasurement or sensing of temperature is performed in structure 442.Rather, the thermal energy is guided by means of radiation through theoptical fiber. This is substantially different from known temperaturemeasuring probes, e.g., the probe disclosed in U.S. Pat. No. 6,419,635,in which the probe performs the measurement and transits the data toexternal location. Device 440 is therefore advantageous both from thestandpoint of manufacturing process and from the standpoints of cost andavailability.

Reference is now made to FIGS. 23 a-b which are schematic illustrationsof an illuminating device 460, according to various exemplaryembodiments of the present invention. Device 460 can be used in a rangeimaging system, e.g., for illuminating the surface to be imaged with apattern.

Device 460 comprises a light source 462 which generates a light beam464, a dynamic beam deflector 466 and an image forming element 468.Light source 462 preferably comprises a laser device which emits laserbeam. The light beam 464 can be either in the visible range or theinfrared range, depending on the application form which device 460 isused. Also contemplated, is a light source which generate a light beamboth in the visible range and in the infrared range, such as one of theIR-50 series, which is commercially available from Scitec InstrumentsLtd, UK.

Beam deflector 466 serves for dynamically deflecting light beam 464 soas to scan the surface of image forming element 468, to define, e.g., araster pattern thereacross. Beam deflector 466 can comprise a movablemirror or an array of movable mirrors, such as, but not limited to, aDigital Micromirror Device™, commercially available from TexasInstruments Inc., USA. Beam deflector 466 can also comprise anelectrooptical element, preferably an electrooptical crystal whichdeflects the light beam in response to electrical bias applied thereto.

Image forming element 468 is better seen in FIG. 23 b which showselement 468 from viewpoint A. As shown, element 468 comprises aplurality of distinguished regions, designated by reference signs 470-1,470-2, . . . 470-M, . . . 470-N. At least a few of the distinguishedregions re preferably designed for forming a different image. Regions470 can be, for example, holographic elements, diffraction gratings andthe like. In any event regions 470 allow selective transmission of lightsuch that light passing through regions 470 constitutes an image.

In operation, when beam 464 scans the surface of element 468, differentimages are formed at different times. Thus, device 460 is capable ofilluminating a surface with a series of patterns in a periodic manner.The scan rate of beam 464 on element 468 is preferably selected to allowrapid change of the formed images. This is advantageous because itfacilitate fast range imaging. For example, the surface can beilluminated by a series of 10 or more patterns within the duration of asingle frame (e.g., 20 milliseconds) hence to increase the rate of rangeimaging by an order of magnitude.

The present embodiments successfully provide a technique forconstructing a three-dimensional spatial representation of a body. Thetechnique is an improvement of a technique commonly known as “structuredlight technique” or “coded light technique”. The technique is based onthe observation that a stripe projected on a non-planar surfaceintersects the surface at a curve which can reflect the characteristicof surface. An image of the curve can be acquired by an imaging deviceimaged to form a plurality of measured points on the plane of imagingdevice, referred to as the imaging plane. The curve and the light sourceproducing the stripe define another plane referred to as the lightplane. There is a projected correspondence between points on the lightplane and points on the imaging plane. Based on the projectedcorrespondence the 3D coordinates of the points on the non-planarsurface can be determined. In order to acquire image of the entiresurface, coded patterns are projected instead of a single stripe, hencethe terms “structured light” or “coded light.”

A major problem with known structured light techniques is that thelateral resolution of the obtained image cannot be enhanced beyond theintrinsic resolution of the projector which used to produce the codedpattern. While many types of imaging devices are capable of acquiringimages at rather small pixel size (of order of tens of microns), highresolution projectors are hardly attainable. For example, a SVGAprojector generates 800 strips. For a projected area of about 40 cm, thewidth of a single stripe (or the gap between adjacent stripes) is abouthalf a millimeter. The use of more sophisticated and expensive projectoronly marginally improve the resolution. An XGA projector, for example,generates 1024 strips, hence can only reduce the resolution by a factorof less than 30%. In both cases, however, it is recognized that thewidth of a single projected element extends over several pixels of theimaging device, and the achievable resolution is dictated by theresolution of the projector.

The present embodiments successfully overcome the aforementionedresolution limitation by providing a method 500 and system 600 forconstructing a three-dimensional spatial representation of a body.

A flowchart diagram describing the method steps of method 500 inaccordance with preferred embodiments of the present invention isprovided in FIG. 24 and a schematic illustration of system 600 inaccordance with preferred embodiments of the present invention isprovided in FIG. 25.

Referring conjointly to FIGS. 24 and 25, method 500 begins at step 502and continues to step 504 in which a body 610 is illuminated using apattern projector 602. In various exemplary embodiments of the inventionprojector 602 projects coded patterns 604 on body 610 in two or moredifferent colors in a manner such that coded patterns of differentcolors are mutually shifted. Shown in FIG. 25 are three mutually shiftedcoded patterns, 604 a, 604 b and 604 c, which may correspond, forexample, to coded patterns of red light, green light and blue light.

Projector 602 can be based on any technology known in the art, such as,but not limited to, LCD, DLP or a combination thereof. Projector 602 canprovide many types pf patterns. For example, a pattern can includeseveral stripes. The stripes can be uniform or they can have a linearslope of light intensity profile. Such pattern allows identifyingseveral points on the stripes. Other types and shapes of patterns arenot excluded from the scope of the present invention.

Broadly speaking, projector 602 comprises a light source 606 and optics608. Light source 606 typically includes a matrix of polychromaticillumination units or cells, each capable of optical output of severalprimary colors (e.g., red, green and blue). Each illumination unit canalso be sub-divided to two or more monochromatic sub-units. Thus, forexample, a polychromatic illumination unit can include a red sub-unit, agreen sub-unit and a blue sub-unit as known in the art. Alternatively,the polychromatic illumination unit can operate without suchsubdivision, as in the case of, for example, DLP projectors. The matrixcan be a passive matrix or an active matrix.

When light source 606 comprises a passive matrix, no light is generatedwithin the unit and the unit is only able to block transmission of lightgenerated by a backlight assembly of the light source, or enablereflection of light generated by a front illumination assembly of thelight source. In this embodiment, each illumination unit comprises colorfilters such as a color wheel or an arrangement of red, green and blue(RGB) filters to provide optical output of different colors. When lightsource 606 comprises an active matrix, each illumination unit radiateslight independently. In this embodiment, each unit can produce whitelight which is then filtered at the sub-unit level by color filters.Alternatively, each sub-unit can comprise a monochromatic light emittingelement such as a light emitting diode or an organic light emittingdiode.

The number of polychromatic illumination units of light source 606 isreferred to as the resolution of projector 602. As will be appreciatedby one ordinarily skilled in the art, the higher the number of pixels,the better the resolution. Known projectors are with resolution of640×480 units (also known as VGA projector), 800×600 units (also knownas SVGA projector), 1024×768 units (also known as XGA projector),1366×768 units (also known as wide XGA or WXGA projector), 1280×1024units (also known as SXGA projector), 1400×1050 units (also known asSXGA+ or SXGAplus projector), and 1600×1200 (also known as UXGAprojector).

Each polychromatic illumination unit is responsible for illuminating aunit area on the illuminated surface, which unit area is also known inthe literature as a “dot” or a “projected pixel”. Since the projectedpixel corresponds to an area on the surface (rather than the physicalarea of the corresponding illuminating unit) its size depends on thedistance between the projector and the illuminated surface, and on thedivergence of the light beam emitted from the illuminating units.Nonetheless, for a given projector and a given projection distance, theprojected pixel can be characterized by a size, such as a diameter or anarea. The resolution of projector 602 dictates the maximal number ofprojected pixels on the illuminated surface. Similarly, for a givencoverage area of projector 602, the resolution dictates the lateraldistance between the centers of adjacent projected pixels of projector602.

Optics 608 optically manipulates the light beam generated by lightsource 606 to provide the coded pattern. Optics 608 can include, forexample, a focusing or collimating element, a dicroic optic system, adiffraction grating, a holographic element, digital micromirror devicechip and the like. Various combinations of such and similar opticalelements are also contemplated. The mutually shift between codedpatterns of different color is preferably achieved by optics 608. Invarious exemplary embodiments of the invention optics 608 redirectsdifferent wavelengths at different redirection angles. This can beachieved, for example, by designing optics 608 to optically manipulatelight having a predetermined wavelength in the visible range (say,wavelength corresponding to a green or greenish light). Since optics 608is designed for a particular wavelength, different optical manipulationsare obtained for different wavelengths.

Projector 602 preferably, but not obligatorily, operates in sequentialmode. In this preferred embodiment, the surface is illuminated such thattwo adjacent patterns of different colors are projected at differenttimes. A pattern of a given color is preferably generated by activatinga collection of illumination units in a manner that in each unit in thecollection emits light as the same wavelength. An adjacent pattern canbe generated by activating the same collection of illumination units toemit light as a different wavelength. Thus, according to a preferredembodiment of the present invention at least two adjacent patterns aregenerated using the same collection of illumination units.

The wavelengths of the patterns can correspond to primary colors of theunits, or alternatively to predetermined blends of primary colors. Whena pattern of a primary color, say a red pattern, is generated, each unitin the collection emits red light. An adjacent pattern can be generatedby activating the same collection, e.g., to emit a green light, anotheradjacent pattern can be generated by activating the same collection toemit a blue light. Preferably, the sequential operation of projector 602is such that a collection of units is activated to emit a pattern of afirst color, then the same collection is activated to emit a pattern ofa second color etc. Subsequently another collection of units isactivated to emit a series of single color patterns and so on.

According to a preferred embodiment of the present invention projector602 is designed and constructed such that coded patterns of differentcolors are mutually shifted by an amount which is lower than thecharacteristic distance between the centers of adjacent projectedpixels. Preferably, coded patterns of different colors are mutuallyshifted by an amount which half, more preferably third thecharacteristic distance between the centers of adjacent projectedpixels.

The present embodiments exploit different response of optics 608 todifferent wavelengths and generates adjacent patterns shifted by lessthan the size of a projected pixel. In various exemplary embodiments ofthe invention projector 602 operates in sequential mode of projector602, so as to avoid mixing between adjacent patterns even though thedistance between the patterns is smaller than the size of a singleprojected pixel. Yet, projector 602 can also operate is a simultaneousmode. In this embodiment, the acquisition (see step 506 and device 612,hereinafter) preferably employs an arrangement of color filters so as toallow identification of adjacent strips. In any event, the effectiveresolution of projector 602 is significantly increased. Preferably, theeffective resolution of projector 602 is three times larger than thenumber of its illumination units.

More preferably, the effective resolution of projector 602 is nine timesthe number of its illumination units. This can be achieved by increasingthe resolution three times in each lateral dimension.

Consider, for example, an RGB projector which produces strips on asurface. There is a certain amount of different locations on the surfacewhich can be illuminated by a stripe. This number generally equals thewidth or length of the surface in units of projected pixels. When theprojector operates in sequential mode, the number of different locationscan be increased by a factor of three. This is because a particularlinear collection of illumination units can project a red stripe on afirst lateral location on the surface, a green stripe on a secondlateral location on the surface, and a blue stripe on a third laterallocation on the surface, where the first, second and third laterallocations are slightly shifted with respect to each other. Yet, thelateral extent of all three locations approximately equals to thediameter of a single projected pixel. Thus, had the collectionillumination units projected a white stripe (formed be a blend of allRGB colors) on the surface, its width would have been about three timeswider than the width of each primary color stripe.

The situation is illustrated in FIGS. 26 a-d, showing the a first stripe702 at lateral location 712 (FIG. 26 a), a second stripe 704 at laterallocation 714 (FIG. 26 b), a third stripe 706 at lateral location 716(FIG. 26 c), and all three stripes extending over lateral location712-716.

Similar consideration can be made for vertical as well as horizontalstrips, in which case the resolution is increased by a factor of 3×3=9.

In various exemplary embodiments of the invention the shift between twoadjacent stripes of different colors is less than the width of a singlestripe. Formally, when the width of a stripe is w, the mutual shiftbetween two adjacent stripes of different colors is X w, where 0<X<1,more preferably 0<X≦0.5, even more preferably 0.3≦X≦0.5, say about ⅓.For example, when the width of a stripe is 0.4 mm and projector 602produces three different primary colors, the mutual shift is about 0.15mm.

Method 500 continues to step 506 in which one or more images the codedpatterns are acquired to provide image data. The acquisition can be doneusing an imaging device 612, such as a CCD or the like. The design andbasic functions of imaging device 612 are well known in the art and arenot described in any detail here. In addition to performing basicfunctions of image acquisition (such as, but not limited to, reading outand synchronizing the CCD chip, background subtraction, auto-exposure,auto-focus etc.), the electronic circuitry of device 612 preferablycontains a memory medium for storing calibration data.

According to a preferred embodiment of the present invention theacquisition is done so as to distinguish between coded patterns ofdifferent colors. Thus, the resolution of imaging device 612 is at leastas high as the effective resolution of projector 602. Additionally,since the coded patterns are generated in sequential manner, theacquisition of image comprises multiple readouts during a singleexposure time. For example, when there are three primary colors, theacquisition of image comprises three readouts during a single exposuretime, e.g., one readout for each generated pattern. Also contemplatedare short exposure times as further detailed herein above (see FIGS. 16a-c and accompanying description).

Method 500 proceeds to step 508 in which the 3D positions of the codedpatterns are calculated based on the image data. The calculation isperformed using an image data processor 614 which is supplemented by anappropriate 3D position calculation algorithm as known in the art.

Broadly speaking, the algorithm preferably locates with the position ofthe coded patterns on the image. Optionally, the intensities of theobtained patterns are compared between each other. Once the patterns areidentified, their 3D coordinates can be determined as known in the art,e.g., by triangulation. The geometric parameters of the system such asthe distance between the light source and the imaging device, at anglesunder which the patterns are emitted, are generally known from thedesign of the system or determined in a suitable calibration process asknown in the art. representative examples of calibration data, include,without limitation, triangulation distance, focal lengths, pixel sizes,angular positions, intensity profile of the coded patterns, and thelike. The calculation of 3D coordinates is typically, but notexclusively, employed in a two stages: a low resolution stage in which3D coordinates of only a portion of the patterns are determined, and ahigh resolution stage in which the 3D coordinates are computed for allpatterns. The calculation of 3D coordinate is preferably executed insuch accuracy so as to allow determination of adjacent patterns ofdifferent colors. In other words, the accuracy of the calculation ispreferably such that allows distinguishing between objects laterallyshifted by an amount which is lower than the distance between adjacentprojected pixels. For example, when the patterns comprise stripes, theaccuracy of calculation is compatible with the distance between twoadjacent stripes.

Typically, about 10-20 patterns each consisting of about 10-50 stripesare sufficient to approximate the geometry of the surface. Thethree-dimensional representation of the surface can be approximatedusing a meshing algorithm as known in the art to provide a triangulatedmesh.

The method ends at step 510.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims. All publications, patents and patentapplications mentioned in this specification are herein incorporated intheir entirety by reference into the specification, to the same extentas if each individual publication, patent or patent application wasspecifically and individually indicated to be incorporated herein byreference. In addition, citation or identification of any reference inthis application shall not be construed as an admission that suchreference is available as prior art to the present invention.

1. A method of calculating a thermal path in a living body, comprising:obtaining a synthesized thermospatial image defined over athree-dimensional spatial representation of the living body and havingthermal data associated with a surface of said three-dimensional spatialrepresentation; identifying at least one thermally distinguishable areain said thermospatial image; and using said thermospatial image and saidthermally distinguishable area for calculating the thermal path.
 2. Themethod of claim 1, further comprising using at least two thermal pathsso as to determine an internal three-dimensional thermallydistinguishable region in the living body.
 3. The method of claim 2,further comprising: obtaining an additional synthesized thermospatialimage representing a different posture of the living body; repeatingsaid thermally distinguishable area identification and said gradientcalculation so as to determine an internal three-dimensional thermallydistinguishable region corresponding to said different posture; andcomparing internal three-dimensional thermally distinguishable regionscorresponding to different postures.
 4. Apparatus for calculating athermal path in a living body, comprising: an input unit for receiving asynthesized thermospatial image defined over a three-dimensional spatialrepresentation of the living body and having thermal data associatedwith a surface of said three-dimensional spatial representation; a areaidentification unit, for identifying at least one thermallydistinguishable area in said synthesized thermospatial image; and acalculator for calculating the thermal path in the living body based onsaid thermospatial image and said thermally distinguishable area.
 5. Theapparatus of claim 4, further comprising a region determination unit,designed and configured for determining an internal three-dimensionalthermally distinguishable region in the living body based on at leasttwo thermal trajectories.
 6. The method of claim 1, wherein said thermalpath is calculated by calculating a spatial gradient of said surface atsaid area.
 7. A method of determining an internal three-dimensionalthermally distinguishable region in the living body, the methodcomprising: obtaining a synthesized thermospatial image defined over athree-dimensional spatial representation of the living body and havingthermal data arranged over a surface of said three-dimensional spatialrepresentation in a plurality of picture-elements each represented by aintensity value or a grey-level; searching for at least one set ofpicture-elements represented by generally similar intensity values orgrey-levels; and for at least one of said at least one set ofpicture-elements, defining a plurality of loci, each locus beingassociated with at least a pair of picture-elements of said set anddefined such that each point of said locus is at equal thermal distancesfrom individual picture-elements of said pair, and using said pluralityof loci for determining the internal three-dimensional thermallydistinguishable region.
 8. Apparatus for determining an internalthree-dimensional thermally distinguishable region in the living body,the apparatus comprising: an input unit for receiving a synthesizedthermospatial image defined over a three-dimensional spatialrepresentation of the living body and having thermal data arranged overa surface of said three-dimensional spatial representation in aplurality of picture-elements each represented by a intensity value or agrey-level; a searching unit for searching for at least one set ofpicture-element represented by generally similar intensity values orgrey-levels; a locus definition unit for defining a plurality of loci,each locus being associated with at least a pair of picture-elements ofsaid set and defined such that each point of said locus is at equalthermal distances from individual picture-elements of said pair; and aregion determination unit for determining the internal three-dimensionalthermally distinguishable region based on said plurality of loci.
 9. Themethod of claim 7, wherein at least one locus of said plurality of lociis a plane.
 10. (canceled)
 11. The method of claim 7, wherein theinternal three-dimensional thermally distinguishable region isdetermined based on intersecting lines of at least a few of saidplurality of loci.
 12. The method of claim 2, further comprisinglocating a source region within said internal three-dimensionalthermally distinguishable region.
 13. The apparatus of claim 5, furthercomprising a source region locator, for locating a source region withinsaid internal three-dimensional thermally distinguishable region. 14.The method of claim 12, wherein said source region is selected from thegroup consisting of a centroid, a weighted centroid and a center-of-massof said internal three-dimensional thermally distinguishable region. 15.A method of determining a number of thermally distinguishable objects inthe living body, the method comprising: obtaining a synthesizedthermospatial image defined over a three-dimensional spatialrepresentation of the living body and having thermal data associatedwith a surface of said three-dimensional spatial representation, saidthermal data being characterized by closed isothermal contourssurrounding at least one thermally distinguished areas on said surface;determining an internal three-dimensional thermally distinguishableregion in the living body based on said synthesized thermospatial image;analyzing said three-dimensional spatial representation so as to definea boundary within said three-dimensional spatial representation, whereinpoints residing on one side of said boundary correspond to a singlethermally distinguished area on said surface while points residing onanother side of said boundary correspond to a plurality of thermallydistinguished areas on said surface; and comparing said internalthree-dimensional thermally distinguishable region with said boundary soas to determine the number of thermally distinguishable objects in theliving body.
 16. The method of claim 15, wherein said determining saidinternal three-dimensional thermally distinguishable region comprises:identifying at least one thermally distinguishable area in saidthermospatial image; calculating a spatial gradient of said surface atsaid area, thereby calculating a thermal path in the living body; andusing at least two thermal trajectories so as to determine said internalthree-dimensional thermally distinguishable region.
 17. The method ofclaim 15, wherein said thermal data is arranged over said surface in aplurality of picture-elements each represented by an intensity value orgrey-level and said determining said internal three-dimensionalthermally distinguishable region comprises: searching for at least oneset of picture-elements represented by generally similar intensityvalues or grey-levels; and for at least one of said at least one set ofpicture-elements, defining a plurality of loci, each locus beingassociated with at least a pair of picture-elements of said set anddefined such that each point of said locus is at equal thermal distancesfrom individual picture-elements of said pair, and using said pluralityof loci for determining said internal three-dimensional thermallydistinguishable region.
 18. Apparatus for determining a number ofthermally distinguishable objects in the living body, the apparatuscomprising: an input unit for receiving a synthesized thermospatialimage defined over a three-dimensional spatial representation of theliving body and having thermal data associated with a surface of saidthree-dimensional spatial representation, said thermal data beingcharacterized by closed isothermal contours surrounding at least onethermally distinguished areas on said surface; a region determinationunit for determining an internal three-dimensional thermallydistinguishable region in the living body based on said synthesizedthermospatial image; an analyzer for analyzing said three-dimensionalspatial representation so as to define a boundary within saidthree-dimensional spatial representation, wherein points residing on oneside of said boundary correspond to a single thermally distinguishedarea on said surface while points residing on another side of saidboundary correspond to a plurality of thermally distinguished areas onsaid surface; and a comparison unit for comparing said internalthree-dimensional thermally distinguishable region with said boundary soas to determine the number of thermally distinguishable objects in theliving body. 19.-20. (canceled)
 21. The method of claim 1, furthercomprising acquiring at least one thermographic image and mapping saidat least one thermographic image on said three-dimensional spatialrepresentation so as to form said synthesized thermospatial image. 22.The method of claim 21, wherein said mapping comprises weighting said atleast one thermographic image according to emissivity data of the livingbody.
 23. The method of claim 21, wherein said at least onethermographic image comprises a plurality of thermographic images. 24.The method of claim 23, wherein at least two of said plurality ofthermographic images are acquired when the living body is at a differentposture.
 25. The method of claim 1, further comprising obtaining atleast one additional synthesized thermospatial image, said at least oneadditional synthesized thermospatial image corresponding to a differentposture of the living body.
 26. The method of claim 21, furthercomprising: obtaining a plurality of three-dimensional spatialrepresentations of the living body; for at least two three-dimensionalspatial representations, analyzing each three-dimensional spatialrepresentation so as to determine expected topology of isothermalcontours on a surface of said three-dimensional spatial representation;and selecting a viewpoint for said at least one thermographic imageand/or a posture of the living body based on said expected topologies.27. The method of claim 21, further comprising: obtaining at least oneadditional three-dimensional spatial representation of the living body,corresponding to a different viewpoint with respect to, and/or adifferent posture of, the living body; based on said internalthree-dimensional thermally distinguishable region in the living body,constructing expected topology of isothermal contours on a surface ofsaid at least one additional three-dimensional spatial representation;obtaining at least one additional synthesized thermospatial imagecorresponding to said different viewpoint and/or said different posture;comparing said at least one synthesized thermospatial image to saidexpected topology of said isothermal contours; and issuing a reportrelating to said comparison.
 28. (canceled)
 29. The method of claim 27,wherein said obtaining said three-dimensional spatial representationcomprises illuminating the body with a pattern in the infrared range,using at least one thermographic imaging device for acquiring at leastone thermographic image of the body and said pattern, calculating rangedata corresponding to said pattern, and using said at least onethermographic image and said range data for constructing thethree-dimensional spatial representation of the body. 30-80. (canceled)81. A method of calculating a thermal path in a body, comprising: (a)associating thermal data with a surface of at least a portion of thebody to thereby generate a thermal data map on said surface; (b)identifying in said thermal data map at least one thermallydistinguishable region; and (c) calculating the thermal path in said atleast a portion of the body based on a surface distribution of said atleast one thermally distinguishable region.
 82. The method of claim 81,wherein said (a) is effected by collecting thermal radiation from saidsurface.
 83. The method of claim 82, further comprising correcting saidcollected thermal radiation for emissivity of tissue in said at leastsaid portion of the body.
 84. The method of claim 81, wherein said atleast one thermally distinguishable region comprises at least twothermally distinguishable region.